Co-doped NiFe carbonate hydroxide hydrate nanosheets with edge effect constructed from spent lithium-ion battery ternary cathodes for oxygen evolution reaction

The recycling of spent lithium-ion batteries (LIBs) has received increasing attention for environment and resource reclamation. Converting LIBs wastes into high-efficiency catalysts is a win-win strategy for realizing resource reclamation and addressing sustainable energy challenges. Herein, we developed a simple method to upcycle spent-LIBs cathode powder into Co-doped NiFe carbonate hydroxide hydrate (Co/NFCH-FF) as a low-cost and efficient oxygen evolution reaction (OER) electrocatalyst. The optimized Co/NFCH-FF electrode appears very competitive OER performances with low overpotentials of 201 and 249 mV at 10 and 100 mA cm-2, respectively, a small Tafel slope of 48.4 mV dec-1, and a high long-term stability. Moreover, we reveal that the existence of Co atoms leads to the formation of a crystalline/amorphous (c/a) interface at the Co/NFCH nanosheet edge, inducing the nanosheets possess a unique edge effect to enhance electric fields and accumulate hydroxide ions (OH-) at the edge during the OER process. Benefiting from edge effect, Co/NFCH-FF shows outstanding intrinsic activity. Furthermore, Co atoms as dopants stabilize the electronic structure of Co/NFCH-FF, enabling Co/NFCH-FF to exhibit excellent catalytic stability. This work provides an effective strategy for converting the end-life LIBs to high-performance multicomponent OER electrocatalysts and proposes new insights into the mechanism of enhanced catalytic activity of Co/NFCH.

A mild and efficient closed-loop recycling strategy for spent lithium-ion battery

As lithium metal resource supply and demand stabilize and prices decrease, the efficient recovery of valuable metals other than lithium from spent lithium-ion batteries is receiving increasing attention. Currently, challenges remain in the selective lithium recovery efficiency and the high cost of regenerating valuable metal slag after lithium extraction, particularly for spent ternary cathode materials. To address these challenges, this study introduces a closed-loop recovery process for spent ternary cathode materials, employing sulfur-assisted roasting to achieve efficient lithium extraction and high-value direct regeneration of ternary leaching residues. At moderate temperatures (500 ℃), LiNixCoyMn1-x-yO2 (NCM) materials undergo a directional transformation of lithium to Li2SO4 in synergy with sulfur and oxygen, achieving a lithium leaching extraction rate of 98.91 %. Additionally, the relatively mild reaction conditions preserve the secondary spherical morphology and uniform distribution of NiCoMn-based oxide residue without introducing adverse impurities, ensuring the successful regeneration of high-value NCM cathode materials (R-NCM). The R-NCM material exhibits good discharge capacity (144.3 mA·h/g at 1 C) and relatively stable cycling performance, with a capacity retention rate of 80 % after 150 cycles. This work provides a viable pathway for the efficient and environmental-friendly pyrometallurgical closed-loop recovery of spent lithium-ion batteries.

Achievements, challenges, and perspectives in the design of polymer binders for advanced lithium-ion batteries

Energy storage devices with high power and energy density are in demand owing to the rapidly growing population, and lithium-ion batteries (LIBs) are promising rechargeable energy storage devices. However, there are many issues associated with the development of electrode materials with a high theoretical capacity, which need to be addressed before their commercialization. Extensive research has focused on the modification and structural design of electrode materials, which are usually expensive and sophisticated. Besides, polymer binders are pivotal components for maintaining the structural integrity and stability of electrodes in LIBs. Polyvinylidene difluoride (PVDF) is a commercial binder with superior electrochemical stability, but its poor adhesion, insufficient mechanical properties, and low electronic and ionic conductivity hinder its wide application as a high-capacity electrode material. In this review, we highlight the recent progress in developing different polymeric materials (based on natural polymers and synthetic non-conductive and electronically conductive polymers) as binders for the anodes and cathodes in LIBs. The influence of the mechanical, adhesion, and self-healing properties as well as electronic and ionic conductivity of polymers on the capacity, capacity retention, rate performance and cycling life of batteries is discussed. Firstly, we analyze the failure mechanisms of binders based on the operation principle of lithium-ion batteries, introducing two models of "interface failure" and "degradation failure". More importantly, we propose several binder parameters applicable to most lithium-ion batteries and systematically consider and summarize the relationships between the chemical structure and properties of the binder at the molecular level. Subsequently, we select silicon and sulfur active electrode materials as examples to discuss the design principles of the binder from a molecular structure point of view. Finally, we present our perspectives on the development directions of binders for next-generation high-energy-density lithium-ion batteries. We hope that this review will guide researchers in the further design of novel efficient binders for lithium-ion batteries at the molecular level, especially for high energy density electrode materials.

Sustainable reprocessing of lithium iron phosphate batteries: A recovery approach using liquid-phase method at reduced temperature

Lithium iron phosphate batteries, known for their durability, safety, and cost-efficiency, have become essential in new energy applications. However, their widespread use has highlighted the urgency of battery recycling. Inadequate management could lead to resource waste and environmental harm. Traditional recycling methods, like hydrometallurgy and pyrometallurgy, are complex and energy-intensive, resulting in high costs. To address these challenges, this study introduces a novel low-temperature liquid-phase method for regenerating lithium iron phosphate positive electrode materials. By using N2H4·H2O as a reducing agent, missing Li+ ions are replenished, and anti-site defects are reduced through annealing. This process restores nearly all missing Li+ ions at 80 °C/6h. After high-temperature sintering at 700 °C/2h, the regenerated LiFePO4 matches commercial LiFePO4 in terms of anti-site defects and exhibits excellent performance with a 97 % capacity retention rate after 100 cycles at 1C. Compared to high-temperature techniques, this low-temperature liquid-phase method is simpler, safer, and more energy-efficient, offering a blueprint for reclaiming discarded LiFePO4 and similar materials.

Reviving Fatigue Surface for Solid-State Upcycling of Highly Degraded Polycrystalline LiNi1-x-yCoxMnyO2 Cathodes

The ongoing tide of spent lithium-ion batteries (LIBs) urgently calls for high-value output in efficient recycling. Recently, direct regeneration has emerged as a novel recycling strategy but fails to repair the irreversible morphology and structure damage of the highly degraded polycrystalline layered oxide materials. Here, this work carries out a solid-state upcycling study for the severely cracked LiNi1-x-yCoxMnyO2 cathodes. The specific single-crystallization process during calcination is investigated and the surface rock salt phase is recognized as the intrinsic obstacle to the crystal growth of the degraded cathodes due to sluggish diffusion in the heterogeneous grain boundary. Accordingly, this work revives the fatigue rock salt phase by restoring a layered surface and successfully reshapes severely broken cathodes into the high-performance single-crystalline particles. Benefiting from morphological and structural integrity, the upcycled single-crystalline cathode materials exhibit an enhanced capacity retention rate of 93.5% after 150 cycles at 1C compared with 61.7% of the regenerated polycrystalline materials. The performance is also beyond that of the commercial cathodes even under a high cut-off voltage (4.5 V) or high operating temperature (45 °C). This work provides scientific insights for the upcycling of the highly degraded cathodes in spent LIBs.

Crystal phase and nanoscale size regulation utilizing the in-situ catalytic pyrolysis of bamboo sawdust in the recycling of spent lithium batteries

Current Li-ion battery (LIB) recycling methods exhibit the disadvantages of low metal recovery efficiencies and high levels of pollution and energy consumption. Here, products generated via the in-situ catalytic pyrolysis of bamboo sawdust (BS) were utilized to regulate the crystal phase and nanoscale size of the NCM cathode to enhance the selective Li extraction and leaching efficiencies of other valuable metals from spent LIBs. The catalytic effect of the NCM cathode significantly promoted the release of gases from BS pyrolysis. These gases (H2, CO, and CH4) finally transformed the crystal phase of the NCM cathode from LiNixCoyMnzO2 into (Ni-Co/MnO/Li2CO3)/C. The size of the spent NCM cathode material was reduced approximately 31.7-fold (from 4.1 μm to 129.2 nm) after roasting. This could be ascribed to the in-situ catalytic decomposition of aromatic compounds generated via the primary pyrolysis of BS into C and H2 on the surface of the cathode material, resulting in the formation of the nanoscale composite (Ni-Co/MnO/Li2CO3)/C. This process enabled the targeted control of the crystal phase and nanoscale size of the material. Water leaching studies revealed a remarkable selective Li extraction efficiency of 99.27 %, and sulfuric acid leaching experiments with a concentration of 2 M revealed high extraction efficiencies of 99.15 % (Ni), 93.87 % (Co), and 99.46 % (Mn). Finally, a novel mechanism involving synergistic thermo-reduction and carbon modification for crystal phase regulation and nanoscale control was proposed. This study provides a novel concept for use in enhancing the recycling of valuable metals from spent LIBs utilizing biomass waste and practices the concept of "treating waste with waste".

Recycling of spent lithium-ion batteries for a sustainable future: recent advancements

Lithium-ion batteries (LIBs) are widely used as power storage systems in electronic devices and electric vehicles (EVs). Recycling of spent LIBs is of utmost importance from various perspectives including recovery of valuable metals (mostly Co and Li) and mitigation of environmental pollution. Recycling methods such as direct recycling, pyrometallurgy, hydrometallurgy, bio-hydrometallurgy (bioleaching) and electrometallurgy are generally used to resynthesise LIBs. These methods have their own benefits and drawbacks. This manuscript provides a critical review of recent advances in the recycling of spent LIBs, including the development of recycling processes, identification of the products obtained from recycling, and the effects of recycling methods on environmental burdens. Insights into chemical reactions, thermodynamics, kinetics, and the influence of operating parameters of each recycling technology are provided. The sustainability of recycling technologies (e.g., life cycle assessment and life cycle cost analysis) is critically evaluated. Finally, the existing challenges and future prospects are presented for further development of sustainable, highly efficient, and environmentally benign recycling of spent LIBs to contribute to the circular economy.

Potential-Regulated Design for Direct Recycling of Degraded LiFePO4 Cathode

The rapid proliferation of power sources equipped with lithium-ion batteries poses significant challenges in terms of post-scrap recycling and environmental impacts, necessitating urgent attention to the development of sustainable solutions. The cathode direct regeneration technologies present an optimal solution for the disposal of degraded cathodes, aiming to non-destructively re-lithiate and straightforwardly reuse degraded cathode materials with reasonable profits and excellent efficiency. Herein, a potential-regulated strategy is proposed for the direct recycling of degraded LiFePO4 cathodes, utilizing low-cost Na2SO3 as a reductant with lower redox potential in the alkaline systems. The aqueous re-lithiation approach, as a viable alternative, not only enables the re-lithiation of degraded cathode while ignoring variation in Li loss among different feedstocks but also utilizes the rapid sintering process to restore the cathode microstructure with desirable stoichiometry and crystallinity. The regenerated LiFePO4 exhibits enhanced electrochemical performance with a capacity of 144 mA h g-1 at 1 C and a high retention of 98% after 500 cycles at 5 C. Furthermore, this present work offers considerable prospects for the industrial implementation of directly recycled materials from lithium-ion batteries, resulting in improved economic benefits compared to conventional leaching methods.

Ion-imprinted aminoguanidine-chitosan for selective recognition of lanthanum (III) from wastewater

Developing a sorbent for the removal of La3+ ions from wastewater offers significant environmental and economic advantages. This study employed an ion-imprinting process to integrate La3+ ions into a newly developed derivative of aminoguanidine-chitosan (AGCS), synthesized via an innovative method. The process initiated with the modification of chitosan by attaching cyanoacetyl groups through amide bonds, yielding cyanoacetyl chitosan (CAC). This derivative underwent further modification with aminoguanidine to produce the chelating AGCS biopolymer. The binding of La3+ ions to AGCS occurred through imprinting and cross-linking with epichlorohydrin (ECH), followed by the extraction of La3+, resulting in the La3+ ion-imprinted sorbent (La-AGCS). Structural confirmation of these chitosan derivatives was established through elemental analysis, FTIR, and NMR. SEM analysis revealed that La-AGCS exhibited a more porous structure compared to the smoother non-imprinted polymer (NIP). La-AGCS demonstrated superior La3+ capture capability, with a maximum capacity of 286 ± 1 mg/g. The adsorption process, fitting the Langmuir and pseudo-second-order models, indicated a primary chemisorption mechanism. Moreover, La-AGCS displayed excellent selectivity for La3+, exhibiting selectivity coefficients ranging from 4 to 13 against other metals. This study underscores a strategic approach in designing advanced materials tailored for La3+ removal, capitalizing on specific chelator properties and ion-imprinting technology.

Unveiling the lithium deintercalation mechanisms in spent lithium-ion batteries via sulfation roasting

Recovery of valuable metals from spent lithium-ion batteries (LIBs) is of great importance for resource sustainability and environmental protection. This study introduced pyrite ore (FeS2) as an alternative additive to achieve the selective recovery of Li2CO3 from spent LiCoO2 (LCO) batteries. The mechanism study revealed that the sulfation reaction followed two pathways. During the initial stage (550 °C-800 °C), the decomposition and oxidation of FeS2 and the subsequent gas-solid reaction between the resulting SO2 and layered LCO play crucial roles. The sulfation of lithium occurred prior to cobalt, resulting in the disruption of layered structure of LCO and the transformation into tetragonal spinel. In the second stage (over 800 °C), the dominated reactions were the decomposition of orthorhombic cobalt sulfate and its combination with rhombohedral Fe2O3 to form CoFe2O4. The deintercalation of Li from LCO by the substitution of Fe and conversion of Co(III)/Fe(II) into Co3O4/CoFe2O4 were further confirmed by density functional theory (DFT) calculation results. This fundamental understanding of the sulfation reaction facilitated the future development of lithium extraction methods that utilized additives to substantially reduce energy consumption.

A raising alarm on the current global electronic waste situation through bibliometric analysis, life cycle, and techno-economic assessment: a review

Electronic waste (E-waste) production worldwide is increasing three times faster than the growth of the global population, and it is predicted that the total volume of E-waste will reach 74 million tonnes by 2030. United Nations warned that unless emissions of heat-trapping gases are drastically reduced, humanity will face catastrophic climate change. We created a bibliometric analysis and discussed the life cycle and techno-economic assessments of the current E-waste situation. We found trending E-waste topics, particularly those related to industrial facilities implementing a circular economy framework and improving the recycling methods of lithium-ion batteries, and this was linked to the topic of electric vehicles. Other research themes included bioleaching, hydrometallurgy, reverse logistics, heavy metal life cycle assessment, and sustainability. These topics can interest industrial factories and scientists interested in these fields. Also, throughout techno-economic assessments, we highlighted several economic and investment opportunities to benefit stakeholders from E-waste recycling. While the rate of E-waste is increasing, consumer education on the proper E-waste management strategies, a collaboration between international organizations with the industrial sector, and legislation of robust E-waste regulations may reduce the harmful effect on humans and the environment and increase the income to flourish national economies.

Toward Circular Energy: Exploring Direct Regeneration for Lithium-Ion Battery Sustainability

Lithium-ion batteries (LIBs) are rapidly developing into attractive energy storage technologies. As LIBs gradually enter retirement, their sustainability is starting to come into focus. The utilization of recycled spent LIBs as raw materials for battery manufacturing is imperative for resource and environmental sustainability. The sustainability of spent LIBs depends on the recycling process, whereby the cycling of battery materials must be maximized while minimizing waste emissions and energy consumption. Although LIB recycling technologies (hydrometallurgy and pyrometallurgy) have been commercialized on a large scale, they have unavoidable limitations. They are incompatible with circular economy principles because they require toxic chemicals, emit hazardous substances, and consume large amounts of energy. The direct regeneration of degraded electrode materials from spent LIBs is a viable alternative to traditional recycling technologies and is a nondestructive repair technology. Furthermore, direct regeneration offers advantages such as maximization of the value of recycled electrode materials, use of sustainable, nontoxic reagents, high potential profitability, and significant application potential. Therefore, this review aims to investigate the state-of-the-art direct LIB regeneration technologies that can be extended to large-scale applications.

Gel polymer electrolytes for rechargeable batteries toward wide-temperature applications

Rechargeable batteries, typically represented by lithium-ion batteries, have taken a huge leap in energy density over the last two decades. However, they still face material/chemical challenges in ensuring safety and long service life at temperatures beyond the optimum range, primarily due to the chemical/electrochemical instabilities of conventional liquid electrolytes against aggressive electrode reactions and temperature variation. In this regard, a gel polymer electrolyte (GPE) with its liquid components immobilized and stabilized by a solid matrix, capable of retaining almost all the advantageous natures of the liquid electrolytes and circumventing the interfacial issues that exist in the all-solid-state electrolytes, is of great significance to realize rechargeable batteries with extended working temperature range. We begin this review with the main challenges faced in the development of GPEs, based on extensive literature research and our practical experience. Then, a significant section is dedicated to the requirements and design principles of GPEs for wide-temperature applications, with special attention paid to the feasibility, cost, and environmental impact. Next, the research progress of GPEs is thoroughly reviewed according to the strategies applied. In the end, we outline some prospects of GPEs related to innovations in material sciences, advanced characterizations, artificial intelligence, and environmental impact analysis, hoping to spark new research activities that ultimately bring us a step closer to realizing wide-temperature rechargeable batteries.

In Situ Constructed Spinel Layer Stabilized Upcycled LiCoO2 for High Performance Lithium-Ion Batteries

With ever-increasing requirements for cathodes in the lithium-ion batteries market, an efficiency and eco-friendly upcycling regeneration strategy is imperative to meet the demand for high-performance cathode materials. Herein, a facile, direct and upcycling regeneration strategy is proposed to restore the failed LiCoO2 and enhance the stability at 4.6 V. Double effects combination of relithiation and outside surface reconstruction are simultaneously achieved via a facile solid-phase sintering method. The evolution process of the Li-supplement and grain-recrystallization is systematically investigated, and the high performance of the upcycled materials at high voltage is comprehensively demonstrated. Thanks to the favorable spinel LiCoxMn2-xO4 surface coating, the upcycled sample displays outstanding electrochemical performance, superior to the pristine cathode materials. Notably, the 1% surface-coated LiCoO2 achieves a high discharge-specific capacity of 207.9 mA h g-1 at 0.1 C and delivers excellent cyclability with 77.0% capacity retention after 300 cycles. Significantly, this in situ created spinel coating layer can be potentially utilized for recycling spent LiCoO2, thus providing a viable, promising recycling strategy insights into the upcycling of degraded cathodes.

Recycling primary lithium batteries using a coordination chemistry approach: recovery of lithium and manganese residues in the form of industrially important materials

In this study, we have investigated the potential use of post-consumer primary lithium metal batteries (LMBs) commonly used in portable electronic devices to recover lithium and manganese in the form of industrially important materials. A direct reaction of lithium-containing electronic waste with a naturally sourced ester, methyl salicylate, combined with a wide range of aliphatic alcohols has been used as a general method for recovering lithium in the form of lithium aryloxides of different nuclearities [Li(OAr)(HOMe)2] (1), [Li(OAr)(HOAr)] (2), [Li(OAr)(HOEt)]2 (3), [Li(OAr)(H2O)]2 (4), [Li4(OAr)4(EGME)2] (5), [Li6(OAr)6] (6-8) for ArOH = methyl salicylate (1, 2, 4, 6), ethyl salicylate (3, 7), 2-methoxyethyl salicylate (5, 8), and EGME = 2-methoxyethanol. The hydrolysis of 7 was then used to synthesize lithium salicylate [Li(Sal)(H2O)]n (10), which is an important antioxidant in the production of oils and grease. The discharged cathode material of Li-MnO2 batteries was investigated as a source from which LiClO4, Li2CO3, LiMn2O4, and Mn2O3 can be recovered by means of water-alcohol extraction or calcination. Particular emphasis was placed on the detailed characterization of all battery components and their decomposition products. LMBs were completely recycled for the first time, and materials were recovered from the cathode and the anode.

Life cycle assessment of secondary use and physical recycling of lithium-ion batteries retired from electric vehicles in China

With the rapid development of the global new energy vehicle industry, how to minimize the environmental impact of the recovery has become a common concern and urgent concern. China is a major production and consumption market for electric vehicles, there are no specific and extensive resource and environmental assessment system for batteries. In this paper, the retired Electric vehicles lithium-ion batteries (LIBs) was the research object, and a specific analysis of the recycling treatment and gradual use stages of power batteries were based on life cycle assessment. Different battery assessment scenarios were established according to the development of battery recycling in China. The results showed that the secondary use has the optimal performance compared to the full-component physical, pyrometallurgical and hydrometallurgy recycling. The results showed that direct recycling has a GWP of 0.037 kg-CO2 eq·kg LIB-1, which is lower than others. Secondary use of LIB accounts for the most emission reductions with Global warming (GWP) as 12.134 kg-CO2 eq·kg LIB-1. The secondary use has the greatest impact on the assessment results, especially in dynamic scenarios. Through a comprehensive comparison of different recycling technologies, the secondary use, increasing the recycling rate, reducing resource, energy consumption and pollution emissions.

Exploring the Optical and Energetic Properties of a Co(II)-Based Mixed Ligand MOF

Due to their remarkable properties, including remarkable porosity and extensive surface area, metal-organic frameworks (MOFs) are being investigated for various applications. Herein, we report the first Co(II)-based mixed ligand MOF, formulated Co4(HTrz)2(d-cam)2.5(μ-OH)3. Its 3D structure framework is composed of helical chains {[Co4(μ3-HTrz)4]8+}n connected by d-camphorate ligand building blocks and featured as an extended structure in an AB-AB fashion. The investigated compound displays a wide absorption range across the visible spectrum, characterized by an optical gap energy of 3.7 eV, indicating its semiconducting nature and efficient sunlight absorption capabilities across various wavelengths. The electrochemical performance demonstrated an excellent reversibility, cyclability, structural stability, as well as a specific capacity of up to 100 cycles at a scan rate of 0.1 mV·s-1 and a current density of 50 mA·g-1. Thus, it showcases its ability to retain the capacity over numerous charge-discharge cycles. Additionally, the investigated sample displayed an impressive rate capability during the Li-ion charge/discharge process. Therefore, the material's remarkable electrochemical properties can be ascribed to the synergistic effects of its large specific surface area of 348.294 m2·g-1 and well-defined pore size distribution of 20.448 Å, making it a promising candidate for high-performance Li-ion batteries.

Resource Recovery of Spent Lithium-Ion Battery Cathode Materials by a Supercritical Carbon Dioxide System

The increasing global market size of high-energy storage devices due to the boom in electric vehicles and portable electronics has caused the battery industry to produce a lot of waste lithium-ion batteries. The liberation and de-agglomeration of cathode material are the necessary procedures to improve the recycling derived from spent lithium-ion batteries, as well as enabling the direct recycling pathway. In this study, the supercritical (SC) CO2 was innovatively adapted to enable the recycling of spent lithium-ion batteries (LIBs) based on facilitating the interaction with a binder and dimethyl sulfoxide (DMSO) co-solvent. The results show that the optimum experimental conditions to liberate the cathode particles are processing at a temperature of 70 °C and 80 bar pressure for a duration of 20 min. During the treatment, polyvinylidene fluoride (PVDF) was dissolved in the SC fluid system and collected in the dimethyl sulfoxide (DMSO), as detected by the Fourier Transform Infrared Spectrometer (FTIR). The liberation yield of the cathode from the current collector reaches 96.7% under optimal conditions and thus, the cathode particles are dispersed into smaller fragments. Afterwards, PVDF can be precipitated and reused. In addition, there is no hydrogen fluoride (HF) gas emission due to binder decomposition in the suggested process. The proposed SC-CO2 and co-solvent system effectively separate the PVDF from Li-ion battery electrodes. Thus, this approach is promising as an alternative pre-treatment method due to its efficiency, relatively low energy consumption, and environmental benign features.

Recycling the Spent LiNi1- x - yMnxCoyO2 Cathodes for High-Performance Electrocatalysts toward Both the Oxygen Catalytic and Methanol Oxidation Reactions

The traditional recycling methods of the spent lithium ion batteries (LIBs) involve the intricate and cumbersome steps. This work proposes a facile method of acid leaching followed by the sulfurization treatment to achieve the high Li leaching efficiency, and obtain high-performance multi-function electrocatalysts for oxygen reduction (ORR), oxygen evolution (OER), and methanol oxidation reactions (MOR) from the spent LIB ternary cathodes. By this method, the Li leaching efficiency from the spent LIB ternary cathode can reach 98.3%, and the transition metal sulfide heterostructures (LNMCO-H-450S) consisting MnS, NiS2, and NiCo2S4 phases can be obtained. LNMCO-H-450S shows the superior bifunctional oxygen catalytic activities with ORR half-wave potential of 0.763 V and OER potential at 10 mA cm-2 of 1.561 V, surpassing most of the state-of-the-art electrocatalysts. LNMCO-H-450S also demonstrates the superior MOR catalytic activity with the potential at 100 mA cm-2 being 1.37 V. Using LNMCO-H-450S as the oxygen catalyst, this work can construct the aqueous and solid-state zinc-air batteries with high power density of 309 and 257 mW cm-2, respectively. This work provides a promising strategy for the efficient recovery of Li, and reutilization of Ni, Co, and Mn from the spent LIB ternary cathodes.

Leaching kinetics of fluorine during the aluminum removal from spent Li-ion battery cathode materials

The high content of aluminum (Al) impurity in the recycled cathode powder seriously affects the extraction efficiency of Nickel, Cobalt, Manganese, and Lithium resources and the actual commercial value of recycled materials, so Al removal is crucially important to conform to the industrial standard of spent Li-ion battery cathode materials. In this work, we systematically investigated the leaching process and optimum conditions associated with Al removal from the cathode powder materials collected in a wet cathode-powder peeling and recycling production line of spent Li-ion batteries (LIBs). Moreover, we specifically studied the leaching of fluorine (F) synergistically happened along with the removal process of Al, which was not concerned about in other studies, but one of the key factors affecting pollution prevention in the recovery process. The mechanism of the whole process including the leaching of Al and F from the cathode powder was indicated by using NMR, FTIR, and XPS, and a defluoridation process was preliminarily investigated in this study. The leaching kinetics of Al could be successfully described by the shrinking core model, controlled by the diffusion process and the activation energy was 11.14 kJ/mol. While, the leaching of F was attributed to the dissolution of LiPF6 and decomposition of PVDF, and the kinetics associated was described by Avrami model. The interaction of Al and F is advantageous to realize the defluoridation to some degree. It is expected that our investigation will provide theoretical support for the large-scale recycling of spent LIBs.

Grave-to-cradle photothermal upcycling of waste polyesters over spent LiCoO2

Lithium-ion batteries (LIBs) and plastics are pivotal components of modern society; nevertheless, their escalating production poses formidable challenges to resource sustainability and ecosystem integrity. Here, we showcase the transformation of spent lithium cobalt oxide (LCO) cathodes into photothermal catalysts capable of catalyzing the upcycling of diverse waste polyesters into high-value monomers. The distinctive Li deficiency in spent LCO induces a contraction in the Co-O6 unit cell, boosting the monomer yield exceeding that of pristine LCO by a factor of 10.24. A comprehensive life-cycle assessment underscores the economic viability of utilizing spent LCO as a photothermal catalyst, yielding returns of 129.6 $·kgLCO-1, surpassing traditional battery recycling returns (13-17 $·kgLCO-1). Solar-driven recycling 100,000 tons of PET can reduce 3.459 × 1011 kJ of electric energy and decrease 38,716 tons of greenhouse gas emissions. This work unveils a sustainable solution for the management of spent LIBs and plastics.

Selective Recovery of Battery-Grade Li2CO3 from Spent NCM Cathode Materials Using a One-Step Method of CO2 Carbonation Recovery Without Acids or Bases

The recovery of spent lithium-ion batteries by traditional acid leaching is limited by serious pollution, complicated technology, and the low purity of Li2CO3. To address the problems of the traditional acid leaching process and increasing demand for decarbonization, a technique for the selective carbonation leaching of Li and the recovery of battery-grade Li2CO3 by a simple concentration precipitation process without acids or bases was developed. The coupling of CO2 and reducing agents could effectively promote the precipitation of MCO3 (M=Ni/Co/Mn) and the selective leaching of Li by decreasing the reducing capability needed for transition metals and decreasing the pH of the solution. The optimal selective leaching process of Li was obtained under 1 MPa CO2 with 20 g/L Na2S2O3 at an L/S ratio of 30 mL/g for 1.5 h. FT-IR, XRD, ICP-MS and other methods were used to reveal the multiphase interfacial reaction mechanism of the carbonation reduction of layered cathode materials, which indicated that the reducing agent Na2S2O3 could promote lattice distortion of the cathode materials and effective separation of Li. In summary, a green and economical method for the selective recovery of battery-grade Li2CO3 using a one-step method of CO2 carbonation recovery in a near-neutral environment was proposed.

Toward Direct Regeneration of Spent Lithium-Ion Batteries: A Next-Generation Recycling Method

The popularity of portable electronic devices and electric vehicles has led to the drastically increasing consumption of lithium-ion batteries recently, raising concerns about the disposal and recycling of spent lithium-ion batteries. However, the recycling rate of lithium-ion batteries worldwide at present is extremely low. Many factors limit the promotion of the battery recycling rate: outdated recycling technology is the most critical one. Existing metallurgy-based recycling methods rely on continuous decomposition and extraction steps with high-temperature roasting/acid leaching processes and many chemical reagents. These methods are tedious with worse economic feasibility, and the recycling products are mostly alloys or salts, which can only be used as precursors. To simplify the process and improve the economic benefits, novel recycling methods are in urgent demand, and direct recycling/regeneration is therefore proposed as a next-generation method. Herein, a comprehensive review of the origin, current status, and prospect of direct recycling methods is provided. We have systematically analyzed current recycling methods and summarized their limitations, pointing out the necessity of developing direct recycling methods. A detailed analysis for discussions of the advantages, limitations, and obstacles is conducted. Guidance for future direct recycling methods toward large-scale industrialization as well as green and efficient recycling systems is also provided.

Synergistic Approach for Selective Leaching and Separation of Strategic Metals from Spent Lithium-Ion Batteries

Recycling spent Li-ion batteries (LIBs) is paramount to pursuing resource efficiency and environmental sustainability. This study introduces a synergistic approach for selectively leaching and separating strategic metals from waste LIBs, representing a more efficient alternative to traditional single-acid-based leaching methods. The research also thoroughly analyzes diverse extraction parameters, aiming to achieve clean metal separation through synergistic concepts rather than single-phase extraction. The outcome of this study is developing a comprehensive downstream process, advancing the cause of sustainable waste management in the LIB industry. Under specific conditions with 0.6 mol/L total acid content (0.5 mol/L tartaric acid + 0.1 mol/L ascorbic acid), 99.9% cobalt and 100% lithium were effectively leached. The subsequent extraction process achieved a clean separation, with 48.3% of cobalt extracted using a mixture of 0.1 mol/L Alamine-336-Cyanex-272 (A-336-Cy-272) from the leach liquor with no coextraction of lithium, and this efficiency was improved to 67.3% by adjusting the pH from 2.44 to 7.5. However, it is worth noting that increasing the extractant concentration led to an antagonistic effect. To further enhance cobalt enrichment in the organic phase, the McCabe-Thiele plot method was recommended, employing saponified Cy-272. Moreover, the regeneration of saponified Cy-272 was investigated, and the stripped solution was processed with NaOH to form Co(OH)2, subsequently converting it into cobalt oxide (Co3O4) through calcination.

A review on spent Mn-containing Li-ion batteries: Recovery technologies, challenges, and future perspectives

Mn-containing Li-ion batteries have become primary power sources for electronic devices and electric vehicles because of their high-energy density, extended cycle life, low cost, and heightened safety. In recent years, Li-ion batteries (LIBs) have undergone rapid updates, paralleling the swift advancement of the lithium battery industry, resulting in a growing accumulation of LIB scraps annually, necessitating comprehensive recovery strategies. This article reviews the recent progress in recovering spent Mn-containing LIBs (SM-LIBs), specifically focusing on LiMn2O4 and ternary LiCoxMnyNizO2 (NCM). Initially, the study analyzes the current resource profile of SM-LIBs and elucidates their service mechanisms. Subsequently, the study explores the recovery of SM-LIBs, discussing various methods such as the hydrometallurgical approach, combined pyrolytic treatment-wet leaching process, bioleaching pathway, and electrochemical extraction. These discussions include recovery processes, reaction principles, and technological features. In addition, this study evaluates the potential applications of these recovery technologies, considering aspects such as complexity, economic viability, energy consumption, environmental sustainability, and scalability. Finally, it summarizes the challenges associated with the comprehensive recovery and resource utilization of SM-LIBs and offers insights into future directions.

A Multifunctional Amino Acid Enables Direct Recycling of Spent LiFePO4 Cathode Material

Lithium iron phosphate (LiFePO4 , LFP) batteries are extensively used in electric vehicles and energy storage due to their good cycling stability and safety. However, the finite service life of lithium-ion batteries leads to significant amounts of retired LFP batteries, urgently required to be recycled by environmentally friendly and effective methods. Here, a direct regeneration strategy using natural and low-cost L-threonine as a multifunctional reductant is proposed. The hydroxyl groups and amino groups in L-threonine act as electron donors and nitrogen sources, respectively. The reductive environment created by L-threonine not only aids in converting the degraded FePO4 phase back to a single LFP phase but also facilitates the elimination of detrimental Li-Fe anti-site defects; thus, reconstructing fast Li+ diffusion channels. Meanwhile, N atoms derived from amino groups are able to dope into carbon layers, generating more active sites and enhancing the conductive properties of LFP particles. The regenerated LFP shows great electrochemical performance with a discharge capacity of 147.9 mAh g-1 at 1 C and a capacity retention of 86% after 500 cycles at 5 C. Further, this approach is also feasible for LFP black mass sourced from practical industrial dismantling lines, providing considerable prospects for the large-scale recycling of LFP batteries.

Direct Regenerating Cathode Materials from Spent Lithium-Ion Batteries

Recycling cathode materials from spent lithium-ion batteries (LIBs) is critical to a sustainable society as it will relief valuable but scarce recourse crises and reduce environment burdens simultaneously. Different from conventional hydrometallurgical and pyrometallurgical recycling methods, direct regeneration relies on non-destructive cathode-to-cathode mode, and therefore, more time and energy-saving along with an increased economic return and reduced CO2 footprint. This review retrospects the history of direct regeneration and discusses state-of-the-art development. The reported methods, including high-temperature solid-state, hydrothermal/ionothermal, molten salt thermochemistry, and electrochemical method, are comparatively introduced, targeting at illustrating their underlying regeneration mechanism and applicability. Further, representative repairing and upcycling studies on wide-applied cathodes, including LiCoO2 (LCO), ternary oxides, LiFePO4 (LFP), and LiMn2 O4 (LMO), are presented, with an emphasis on milestone cases. Despite these achievements, there remain several critical issues that shall be addressed before the commercialization of the mentioned direct regeneration methods.

Homogeneous Repair of Highly Degraded Ni-Rich Cathode Material with Spent Lithium Anode

Direct regeneration of spent lithium-ion batteries has received wide attention owing to its potential for resource reuse and environmental benefits. The repair effect of direct regeneration methods undergoing heterogeneous repair process is usually inferior, while homogenous repair process plays a vital role to achieve satisfactory repair results. However, the practical applications of current homogeneous repair methods are challenged by the complex operations and relatively high costs owing to the requirement of additional heating or pressurization. Herein, this work proposes a simple strategy to achieve homogeneous repair of spent cathode materials under relatively mild conditions by uniformly precoating lithium source at room temperature and atmospheric pressure. Followed by annealing, highly degraded LiNi0.83 Co0.12 Mn0.05 O2 with severe Li deficiency and irreversible phase transition is repaired to have an initial capacity of 181.6 mAh g-1 and capacity retention of 80.7% after 150 cycles at 0.5 C. The lithium source used in this strategy is from the spent lithium anode. Moreover, this strategy is suitable for the direct regeneration of various layer oxide cathode materials with different failure degrees. This work provides both theoretical guidance and practical examples for the straightforward, effective, and universally applicable direct regeneration methods.

Short-Process Regeneration of Highly Stable Spherical LiCoO2 Cathode Materials from Spent Lithium-Ion Batteries through Carbonate Precipitation

High-efficacy recycling of spent lithium cobalt oxide (LiCoO2 ) batteries is one of the key tasks in realizing a global resource security strategy due to the rareness of lithium (Li) and cobalt (Co) resources. However, it is of great significance to develop the innovative recycle methods for spent LiCoO2 , simultaneously realizing the efficient recovery of valuable elements and the regeneration of high-performance LiCoO2 . Herein, a novel strategy of regenerating LiCoO2 cathode is proposed, which involves the preparation of micro-spherical aluminum (Al)-doped lithium-lacked precursor (Li2x Co1-x-y Al2/3y CO3, remarked as "PLCAC") via ammonium bicarbonate coprecipitation. The comprehensive conditions affecting particle growth kinetics, morphology and particle size the has been investigated in detail by physical characterizations and electrochemical measurements. And the optimized Al-doped LiCoO2 materials with high-density sphericity (LiCo1-z Alz O2 , remarked as "LCAO") shows a high initial specific capacity of 161 mAh g-1 at 0.1 C and excellent capacity retention of 99.5 % within 100 cycles at 1 C in the voltage range of 2.8 to 4.3 V. Our work provides valuable insights into the featured design of LiCoO2 precursors and cathode materials from spent LiCoO2 batteries, potentially guaranteeing the high-efficacy recycling and utilization of strategic resources.

Ultra-Fast Recyclable and Value-Added Desulfation Method for Spent Lead Paste via Dual Intensification Processes

The new low-cost clean pre-desulfation technology is very important in pyrometallurgy and hydrometallurgy. However, traditional reactors have low space-time yield and desulfation rate, resulting in high energy consumption and SO2 emissions in the industrial desulfation processes. Herein, dual rotating liquid film reactors (RLFRs) and lime are proposed to construct a recyclable, ultra-fast, and value-added desulfation method. Parameter optimization and kinetic calculations prove that the above reactions are controlled by internal diffusion, revealing that RLFR promotes the mass transfer and reaction rate. The new process greatly shortens the desulfation time of lead paste from 40 min to 10 s with a high desulfation rate of 99.7%, and the sulfation time of lime from 30 min to 30 s with a sulfation rate of 98.6% with a net profit of 55.99 ¥/ton by cost accounting. Moreover, ten batches of continuous scale-up experiments demonstrate the stability of processes, the desulfation and sulfation rates are kept at 99.7% and 98.2%, which greatly reduces the emissions of waste desulfate liquor. This work provides a new universal strategy for a sustainable, low-cost, and clean desulfation method of waste resources to achieve technical and economic feasibility.

Recovery of LiCoO2 and graphite from spent lithium-ion batteries by molten-salt electrolysis

The recovery of spent lithium-ion batteries has not only economic value but also ecological benefits. In this paper, molten-salt electrolysis was employed to recover spent LiCoO2 batteries, in which NaCl-Na2CO3 melts were used as the electrolyte, the graphite rod and the mixtures of the spent LiCoO2 cathode and anode were used as the anode and cathode, respectively. During the electrolysis, the LiCoO2 was electrochemically reduced to Co, and Li+ and O2- entered into the molten salt. The O2- was discharged at the anode to generate CO2 and formed Li2CO3. After electrolysis, the cathodic products were separated by magnetic separation to obtain Co and graphite, and Li2CO3 was recovered by water leaching. The recovery efficiencies of Li, Co, and graphite reached 99.3%, 98.1%, and 83.6%, respectively. Overall, this paper provides a simple and efficient electrochemical method for the simultaneous recovery of the cathode and the anode of spent LiCoO2 batteries.

In situ detection of reactive oxygen species spontaneously generated on lead acid battery anodes: a pathway for degradation and self-discharge at open circuit

Prospects for refurbishing and recycling energy storage technologies such as lead acid batteries (LABs) prompt a better understanding of their failure mechanisms. LABs suffer from a high self-discharge rate accompanied by deleterious hard sulfation processes which dramatically decrease cyclability. Furthermore, the evolution of H2, CO, and CO2 also poses safety risks. Despite the maturity of LAB technologies, the mechanisms behind these degradation phenomena have not been well established, thus hindering attempts to extend the cycle life of LABs in a sustainable manner. Here, we investigate the effect of the oxygen reduction reaction (ORR) on the sulfation of LAB anodes under open circuit (OC). For the first time, we found that the sulfation reaction is significantly enhanced in the presence of oxygen. Interestingly, we also report the formation of reactive oxygen species (ROS) during this process, known to hamper cycle life of batteries via corrosion. Electron spin resonance (ESR) and in situ scanning electrochemical microscopy (SECM) unambiguously demonstrated the presence of OH˙ and of H2O2 as the products of spontaneous ORR on LAB anodes. High temporal resolution SECM measurements of the hydrogen evolution reaction (HER) during LAB anode corrosion displayed a stochastic nature, highlighting the value of the in situ experiment. Balancing the ORR and HER prompts self-discharge while reaction of the carbon additives with highly oxidizing ROS may explain previously reported parasitic reactions generating CO and CO2. This degradation mode implicating ROS and battery corrosion impacts the design, operation, and recycling of LABs as well as upcoming chemistries involving the ORR.

Selective leaching process for efficient and rapid recycling of spent lithium iron phosphate batteries

With the continuous development of new energy vehicles, the number of decommissioned lithium iron phosphate (LiFePO4) batteries has been constantly increasing. Therefore, it is necessary to recover metal from spent LiFePO4 batteries due to the high potential for environmental protection and high resource value. In this study, sodium persulfate (Na2S2O8) was selected as the oxidant to regulate and control the oxidation state and proton activity of the leaching solution through its high oxidizing ability. Selective recovery of lithium from LiFePO4 batteries was achieved by oxidizing LiFePO4 to iron phosphate (FePO4) during the leaching process. This paper reports an extensive investigation of the effects of various factors, including the acid concentration, initial volume fraction of the oxidant, reaction temperature, solid-liquid ratio, and reaction time, on lithium leaching. Li+ reached a high leaching rate of 93.3% within 5 minutes even at a low concentration of sulphuric acid (H2SO4), and high-purity lithium carbonate (Li2CO3) was obtained through impurity removal and precipitation reactions. In addition, the leaching mechanism was analysed by both X-ray diffraction and X-ray photoelectron spectroscopy characterization. The results show that the obtained high lithium-ion (Li+) leaching efficiency and fast Li+ leaching time can be ascribed to the superior oxidizing properties of Na2S2O8 and the stability of the crystal structure of LiFePO4 during the oxidative leaching process. The adopted method has significant advantages in terms of safety, efficiency and environmental protection, which are conducive to the sustainable development of lithium batteries.

Fluorescent and chromogenic organic probes to detect group 10 metal ions: design strategies and sensing applications

Group 10 metals including Ni, Pd and Pt have been extensively applied in various essential aspects of human social life, material science, industrial manufactures, medicines and biology. The ionic forms of these metals are involved in several biologically important processes due to their strong binding capability towards different biomolecules. However, the mishandling or overuse of such metals has been linked to serious contamination of our ecological system, more specifically in soil and water bodies with acute consequences. Therefore, the detection of group 10 metal ions in biological as well as environmental samples is of huge significance from the human health point of view. Related to this, considerable efforts are underway to develop adequately efficient and facile methods to achieve their selective detection. Optical sensing of metal ions has gained increasing attention of researchers, particularly in the environmental and biological settings. Innovatively designed optical probes (fluorescent or colorimetric) are usually comprised of three basic components: an explicitly tailored receptor unit, a signalling unit and a clearly defined reporter unit. This review deals with the recent progress in the design and fabrication of fluorescent or colorimetric organic sensors for the detection of group 10 metal ions (Ni(II), Pd(II) and Pt(II)), with attention to the general aspects for design of such sensors.

Potential Controllable Redox Couple for Mild and Efficient Lithium Recovery from Spent Batteries

The prosperity of the lithium-ion battery market is dialectically accompanied by the depletion of corresponding resources and the accumulation of spent batteries. It is an urgent priority to develop green and efficient battery recycling strategies for helping ease resources and environmental pressures at the current stage. Here, we propose a mild and efficient lithium extracting strategy based on potential controllable redox couples. Active lithium in the spent battery without discharging is extracted using a series of tailored aprotic solutions comprised of polycyclic aromatic hydrocarbons and ethers. This ensures a safe yet efficient recycling process with nearly ≈100 % lithium recovery. We further investigate the Li+ -electron concerted redox reactions and the effect of solvation structure on kinetics during the extraction, and broaden the applicability of the Li-PAHs solution. This work can stimulate new inspiration for designing novel solutions to meet efficient and sustainable demands in recycling batteries.

Direct recycling of spent Li-ion batteries: Challenges and opportunities toward practical applications

With the exponential expansion of electric vehicles (EVs), the disposal of Li-ion batteries (LIBs) is poised to increase significantly in the coming years. Effective recycling of these batteries is essential to address environmental concerns and tap into their economic value. Direct recycling has recently emerged as a promising solution at the laboratory level, offering significant environmental benefits and economic viability compared to pyrometallurgical and hydrometallurgical recycling methods. However, its commercialization has not been realized in the terms of financial feasibility. This perspective provides a comprehensive analysis of the obstacles that impede the practical implementation of direct recycling, ranging from disassembling, sorting, and separation to technological limitations. Furthermore, potential solutions are suggested to tackle these challenges in the short term. The need for long-term, collaborative endeavors among manufacturers, battery producers, and recycling companies is outlined to advance fully automated recycling of spent LIBs. Lastly, a smart direct recycling framework is proposed to achieve the full life cycle sustainability of LIBs.

Enabling Future Closed-Loop Recycling of Spent Lithium-Ion Batteries: Direct Cathode Regeneration

The rapid proliferation of electric vehicles equipped with lithium-ion batteries (LIBs) presents serious waste management challenges and environmental hazards for recyclers after scrap. Closed-loop recycling contributes to the sustainable development of batteries and plays an important role in mitigating raw material shortages and supply chain risks. Herein, current direct cathode regeneration methods for industrialized recycling are outlined and evaluated. Different regeneration methods for spent cathode materials are summarized, which provide a new perspective for realizing closed-loop recycling of LIBs. A reference recycling route for retrofitting existing cathode production lines is proposed and minimizes the costs. In addition to promoting the industrialization of direct cathode recycling, the environmental, economic, and political benefits of battery recycling are also highlighted.

Direct selective leaching of lithium from industrial-grade black mass of waste lithium-ion batteries containing LiFePO4 cathodes

Demand for lithium-ion batteries (LIBs) is projected to maintain unprecedented acceleration for decades, towards satisfying international climate and source objectives. LIB wastes pose a threat to the environment, but also may be considered a strategic, high-grade resource. Yet, recycling the black mass of waste LIBs, which contains plastic, C, Li, Fe, Ni, Co, Mn, Cu, and Al, is very complex. Herein, the direct selective leaching of Li from the industrial-grade black mass powder of waste LIBs is proposed for the first time. Results demonstrated that the leaching efficiency of Li is shown to exceed 97%, while other metals remain below 1%. The mechanism of selective leaching was also investigated in this study. Under the experimental conditions, Fe is not leached out and remains in the form of solid FePO4. As for other impurity metal elements, they are removed from the solution due to the alkaline environment of the post-leaching solution and the adsorption effect of the anodic carbon. Furthermore, the alkaline post-leaching solution can avoid the neutralizing stage before the precipitation of lithium salts. This highly efficient and Li-selective leaching strategy offers a broadly applicable approach to reclaiming critical energy minerals from the black mass of wasted LIBs.

Probing Hybrid LiFePO4/FePO4 Phases in a Single Olive LiFePO4 Particle and Their Recovering from Degraded Electric Vehicle Batteries

The recycling of LiFePO4 from degraded lithium-ion batteries (LIBs) from electric vehicles (EVs) has gained significant attention due to resource, environment, and cost considerations. Through neutron diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy, we revealed continuous lithium loss during battery cycling, resulting in a Li-deficient state (Li1-xFePO4) and phase separation within individual particles, where olive-shaped FePO4 nanodomains (5-10 nm) were embedded in the LiFePO4 matrix. The preservation of the olive-shaped skeleton during Li loss and phase change enabled materials recovery. By chemical compensation for the lithium loss, we successfully restored the hybrid LiFePO4/FePO4 structure to pure LiFePO4, eliminating nanograin boundaries. The regenerated LiFePO4 (R-LiFePO4) exhibited a high crystallinity similar to the fresh counterpart. This study highlights the importance of topotactic chemical reactions in structural repair and offers insights into the potential of targeted Li compensation for energy-efficient recycling of battery electrode materials with polyanion-type skeletons.

Reaction-passivation mechanism driven materials separation for recycling of spent lithium-ion batteries

Development of effective recycling strategies for cathode materials in spent lithium-ion batteries are highly desirable but remain significant challenges, among which facile separation of Al foil and active material layer of cathode makes up the first important step. Here, we propose a reaction-passivation driven mechanism for facile separation of Al foil and active material layer. Experimentally, >99.9% separation efficiency for Al foil and LiNi0.55Co0.15Mn0.3O2 layer is realized for a 102 Ah spent cell within 5 mins, and ultrathin, dense aluminum-phytic acid complex layer is in-situ formed on Al foil immediately after its contact with phytic acid, which suppresses continuous Al corrosion. Besides, the dissolution of transitional metal from LiNi0.55Co0.15Mn0.3O2 is negligible and good structural integrity of LiNi0.55Co0.15Mn0.3O2 is well-maintained during the processing. This work demonstrates a feasible approach for Al foil-active material layer separation of cathode and can promote the green and energy-saving battery recycling towards practical applications.

Cost, energy, and carbon footprint benefits of second-life electric vehicle battery use

The manuscript reviews the research on economic and environmental benefits of second-life electric vehicle batteries (EVBs) use for energy storage in households, utilities, and EV charging stations. Economic benefits depend heavily on electricity costs, battery costs, and battery performance; carbon benefits depend largely on the electricity mix charging the batteries. Environmental performance is greatest when used to store renewable energy such as wind and solar power. Inconsistent system boundaries make it challenging to compare the life cycle carbon footprint across different studies. The future growth of second-life EVB utilization faces several challenges, including the chemical and electrical properties and states of health of retired EVBs, the rapidly decreasing costs of new batteries, and different operational requirements. Measures to mitigate these challenges include the development of efficient diagnostic technologies, comprehensive test standards, and battery designs suitable for remanufacturing. Further research is needed based on real-world operational data and harmonized approaches.

Rejuvenation of aged graphite anodes from spent lithium-ion batteries via a facile surface treatment strategy

In this study, we present a facile formic acid treatment to rejuvenate aged graphite anodes from spent lithium-ion batteries (LIBs) without damaging the electrode structure. This method effectively removes the interfacial blocking layer, improving capacity and rate performance. Our approach contributes to sustainable battery recycling strategies for spent graphite anodes in LIBs.

Recycling Hazardous and Valuable Electrolyte in Spent Lithium-Ion Batteries: Urgency, Progress, Challenge, and Viable Approach

Recycling spent lithium-ion batteries (LIBs) is becoming a hot global issue due to the huge amount of scrap, hazardous, and valuable materials associated with end-of-life LIBs. The electrolyte, accounting for 10-15 wt % of spent LIBs, is the most hazardous substance involved in recycling spent LIBs. Meanwhile, the valuable components, especially Li-based salts, make recycling economically beneficial. However, studies of electrolyte recycling still account for only a small fraction of the number of spent LIB recycling papers. On the other hand, many more studies about electrolyte recycling have been published in Chinese but are not well-known worldwide due to the limitations of language. To build a bridge between Chinese and Western academic achievements on electrolyte treatments, this Review first illustrates the urgency and importance of electrolyte recycling and analyzes the reason for its neglect. Then, we introduce the principles and processes of the electrolyte collection methods including mechanical processing, distillation and freezing, solvent extraction, and supercritical carbon dioxide. We also discuss electrolyte separation and regeneration with an emphasis on methods for recovering lithium salts. We discuss the advantages, disadvantages, and challenges of recycling processes. Moreover, we propose five viable approaches for industrialized applications to efficiently recycle electrolytes that combine different processing steps, ranging from mechanical processing with heat distillation to mechanochemistry and in situ catalysis, and to discharging and supercritical carbon dioxide extraction. We conclude with a discussion of future directions for electrolyte recycling. This Review will contribute to electrolyte recycling more efficiently, environmentally friendly, and economically.

Rapid extraction of valuable metals from spent LiNixCoyMn1-x-yO2 cathodes based on synergistic effects between organic acids

The slow rate of organic acid leaching is the main factor hindering the ecological recycling of spent lithium-ion battery (LIB) cathode materials. Here, a mixed green reagent system of ascorbic acid and acetic acid is proposed to leach valuable metal ions from the spent LIBs cathode materials rapidly. In 10 min, 94.93% Li, 95.09% Ni, 97.62% Co, and 96.98% Mn were leached, according to the optimization results. Kinetic studies and material characterization technologies like XRD, SEM, XPS, UV-vis, and FTIR show that the "diffusion" and "stratification" effects of acetic acid contribute to the dual-function leaching agent ascorbic acid quickly extract metal ions from spent LiNi0.5Co0.3Mn0.2O2 (NCM532) materials at a mild temperature. In addition, the density-functional theory (DFT) calculations of spent NCM532 structural surfaces and leaching agents show that the fast leaching of valuable metal ions is due to the synergy between ascorbic acid and acetic acid. These results provided an approachable thinking for developing advanced and environmentally friendly strategies for recycling spent LIB cathode materials.

High-efficiency selective leaching of valuable metals from spent lithium-ion batteries: Effects of Na2S2O8 on the leaching of metals

A new method was presented for the high-efficiency selective leaching of Li and the efficient recovery of transition metals (TMs) from the cathode materials of spent lithium-ion batteries (spent LIBs). Selective leaching of Li was achieved by carbothermic reduction roasting and leaching with Na₂S₂O₈. After reduction roasting, high-valence TMs were reduced to low-valence metals or metal oxides, and Li was converted to Li₂CO₃. Then Na₂S₂O₈ solution selectively extracted 94.15% of Li from roasted product with leaching selectivity of more than 99%. At last, TMs were leached with H₂SO₄ without adding reductant with the leaching efficiency of metals all exceeding 99%. Na₂S₂O₈ added during the leaching process destroyed the agglomerated structure of the roasted product to open the way Li entered the solution. Under the oxidative environment of Na₂S₂O₈ solution, TMs would not be extracted. At the same time, it helped to regulate the phase of TMs and improved the extraction of TMs. Furthermore, the phase transformation mechanism of roasting and leaching was discussed through thermodynamic analysis, XRD, XPS, and SEM-EDS. This process not only realized the selectively comprehensive recycling of valuable metals in spent LIBs cathode materials; but also followed the principle of green chemistry.

A Critical Review on the Recycling Strategy of Lithium Iron Phosphate from Electric Vehicles

Electric vehicles (EVs) are one of the most promising decarbonization solutions to develop a carbon-negative economy. The increasing global storage of EVs brings out a large number of power batteries requiring recycling. Lithium iron phosphate (LFP) is one of the first commercialized cathodes used in early EVs, and now gravimetric energy density improvement makes LFP with low cost and robustness popular again in the market. Developments in LFP recycling techniques are in demand to manage a large portion of the EV batteries retired both today and around ten years later. In this review, first the operation and degradation mechanisms of LFP are revisited aiming to identify entry points for LFP recycling. Then, the current LFP recycling methods, from the pretreatment of the retired batteries to the regeneration and recovery of the LFP cathode are summarized. The emerging direct recovery technology is highlighted, through which both raw material and the production cost of LFP can be recovered. In addition, the current issues limiting the development of the LIBs recycling industry are presented and some ideas for future research are proposed. This review provides the theoretical basis and insightful perspectives on developing new recycling strategies by outlining the whole-life process of LFP.

Novel PbO@C composite material directly derived from spent lead-acid batteries by one-step spray pyrolysis process

A one-step spray pyrolysis process is investigated for the first time in the field of spent lead-acid batteries (LABs) recycling. The spent lead paste that derived from spent LAB is desulfurized and then leached to generate the lead acetate (Pb(Ac)₂) solution, which is then sprayed directly into a tube furnace to prepare the lead oxide (PbO) product by pyrolysis. The low-impurity lead oxide product (9 mg/kg Fe and 1 mg/kg Ba) is obtained under the optimized conditions (the temperature of 700 °C, the pumping rate of 50 L/h, and the spray rate of 0.5 mL/min). The major crystalline phases of the synthesized products are identified to be α-PbO and β-PbO. In the spray pyrolysis process, Pb(Ac)₂ droplets are sequentially transformed into various intermediate products: H₂O(g)@Pb(Ac)₂ solution, Pb(Ac)₂ crystals@PbO, and the final PbO@C product. Owning its carbon skeleton structure, the recovered PbO@C product (carbon content of 0.14%) shows better performance than the commercial ball-milled lead oxide powder in battery tests, with higher initial capacity and better cycling stability. This study could provide a strategy for the short-route recovery of spent LABs.

Direct Electrochemical Leaching Method for High-Purity Lithium Recovery from Spent Lithium Batteries

Recovering lithium from lithium batteries (LIBs) is a promising approach for sustainable ternary lithium battery (T-LIB) development. Current lithium recovery methods from spent T-LIBs mainly concentrated on chemical leaching methods. However, chemical leaching relying on the additional acid seriously threatens the global environment and nonselective leaching also leads to low Li recovery purity. Here, we first reported a direct electro-oxidation method for lithium leaching from spent T-LIBs (Li_0.8Ni_0.6Co_0.2Mn_0.2O₂); 95.02% of Li in the spent T-LIBs was leached under 2.5 V in 3 h. Meanwhile, nearly 100% Li recovery purity was also achieved, attributed to no other metal leaching and additional agents. We also clarified the relationship between lithium leaching and other metals during the electro-oxidation of spent T-LIBs. Under the optimized voltage, Ni and O maintain the electroneutrality in the structure assisting Li leaching, while Co and Mn maintain their valence states. A direct electro-oxidation Li leaching approach achieves high Li recovery purity and meanwhile overcomes the secondary pollution problem.

Research on the high-efficiency crushing, sorting and recycling process of column-shaped waste lithium batteries

The efficient and environmentally friendly recycling technology of waste lithium batteries has become a research hotspot, in which mechanical crushing is an important part of the recycling process. Through experimental methods, the compressive and impact properties of columnar lithium batteries were studied, and the crushing product characteristics and crushing efficiency of the single tear crushing method, single hammer crushing method, and two-step crushing method were investigated. The study shows that the two-step crushing method could achieve 100 % dissociation of all battery components, and the crushed products can be recycled according to their particle size distribution characteristics. The power consumption of the two-step crushing method was only 23.59 % of that of a single hammer crusher, and the reduction of carbon dust emission in the crushing process was as high as 76.29 %. The high crushing efficiency and environmentally friendly of the two-step crushing method are of great practical significance for the subsequent industrial promotion of waste battery recycling.