Biomorphic carbon derived from corn husk as a promising anode materials for potassium ion battery

Designing Heterodiatomic Carbon Hydrangea Superstructures via Machine Learning-Regulated Solvent-Precursor Interactions for Superior Zinc Storage

Carbon superstructures with exquisite morphologies and functionalities show appealing prospects in energy realms, but the systematic tailoring of their microstructures remains a perplexing topic. Here, hydrangea-shaped heterodiatomic carbon superstructures (CHS) are designed using a solution phase manufacturing route, wherein machine learning workflow is applied to screen precursor-matched solvent for optimizing solvent-precursor interaction. Based on the established solubility parameter model and molecular growth kinetics simulation, ethanol as the optimal solvent stimulates thermodynamic solubilization and growth of polymeric intermediates to evoke CHS. Featured with surface-active motifs and consecutive charge transfer paths, CHS allows high accessibility of zincophilic sites and fast ion migration with low energy barriers. A anion-cation hybrid charge storage mechanism of CHS cathode is disclosed, which entails physical alternate uptake of Zn2+/CF3SO3 - ions at electroactive sites and chemical bipedal redox of Zn2+ ions with carbonyl/pyridine motifs. Such a beneficial electrochemistry contributes to all-round improvement in Zn-ion storage, involving excellent capacities (231 mAh g-1 at 0.5 A g-1; 132 mAh g-1 at 50 A g-1), high energy density (152 Wh kg-1), and long-lasting cyclability (100 000 cycles). This work expands the design versatilities of superstructure materials and will accelerate experimental procedures during carbon manufacturing through machine learning in the future.

Biomass-Derived Materials for Advanced Rechargeable Batteries

Biomass-derived materials generally exhibit uniform and highly-stable hierarchical porous structures that can hardly be achieved by conventional chemical synthesis and artificial design. When used as electrodes for rechargeable batteries, these structural and compositional advantages often endow the batteries with superior electrochemical performances. This review systematically introduces the innate merits of biomass-derived materials and their applications as the electrode for advanced rechargeable batteries, including lithium-ion batteries, sodium-ion batteries, potassium-ion batteries, and metal-sulfur batteries. In addition, biomass-derived materials as catalyst supports for metal-air batteries, fuel cells, and redox-flow batteries are also included. The major challenges for specific batteries and the strategies for utilizing biomass-derived materials are detailly introduced. Finally, the future development of biomass-derived materials for advanced rechargeable batteries is prospected. This review aims to promote the development of biomass-derived materials in the field of energy storage and provides effective suggestions for building advanced rechargeable batteries.

Si anode with high initial Coulombic efficiency, long cycle life, and superior rate capability by integrated utilization of graphene and pitch-based carbon

A variety of strategies have been developed to enhance the cycling stability of Si-based anodes in lithium-ion batteries. Although significant progress has been made in enhancing the cycling stability of Si-based anodes, the low initial Coulombic efficiency (ICE) remains a significant challenge to their commercial application. Herein, pitch-based carbon (C) coated Si nanoparticles (NPs) were wrapped by graphene (G) to obtain Si@C/G composite with a small specific surface area of 11.3 m2g-1, resulting in a high ICE of 91.2% at 500 mA g-1. Moreover, the integrated utilization of graphene and soft carbon derived from the low-cost petroleum pitch strongly promotes the electrical conductivity, structure stability, and reaction kinetics of Si NPs. Consequently, the synthesized Si@C/G with a Si loading of 54.7% delivers large reversible capacity (1191 mAh g-1at 500 mA g-1), long cycle life over 200 cycles (a capacity retention of 87.1%), and superior rate capability (952 mAh g-1at 1500 mA g-1). When coupled with a homemade LiNi0.8Co0.1Mn0.1O2(NCM811) cathode in a full cell, it exhibits a promising cycling stability for 200 cycles. This work presents an innovative approach for the manufacture of Si-based anode materials with commercial application.

Hydrangea-like MoS2/carbon dots anode for high-performance sodium storage

Owing to their quantum size, edge effects, and abundant surface functional groups, carbon dots (CDs) have attracted significant attention. In this study, chitin-derived carbon dots (CT-CDs) were prepared and used to synthesize MoS2/CT-CDs. The abundant functional groups on the surface of the CT-CDs facilitated the orderly arrangement of MoS2 nanosheets, resulting in a hydrangea-like structure. When employed as the anode in a sodium-ion battery, MoS2/CT-CDs exhibited an excellent initial charging capacity of 492.6 mAh·g-1 at 0.1 A·g-1 with an initial Coulomb efficiency of 74.4%. Even after 100 cycles, the reversible capacity remained at 338.9 mAh·g-1. Furthermore, the reversible capacity of MoS2/CT-CDs remained at 219.9 mAh·g-1 after 260 cycles when subjected to 1 A·g-1. The hydrangea-like structure of MoS2/CT-CDs, with expanded layer spacing, enhances ion/electron transport while providing additional active sites for sodium-ion storage, resulting in exceptional cycling and rate performances.

Cattail-Grass-Derived Porous Carbon as High-Capacity Anode Material for Li-Ion Batteries

Cattail-grass-derived porous carbon as high-capacity anode materials were prepared via high-temperature carbonization and activation with KOH. The samples exhibited different structures and morphologies with increasing treatment time. It was found that the cattail grass with activation treatment-1 (CGA-1) sample obtained at 800 °C for 1 h presented excellent electrochemical performance. As an anode material for lithium-ion batteries, CGA-1 showed a high charge-discharge capacity of 814.7 mAh g-1 at the current density of 0.1 A g-1 after 400 cycles, which suggests that it has a great potential for energy storage.

Turbostratic Lattice and Electronegativity Modification Jointly Enabled an Ultra-High-Rate and Long-Lived Carbon Anode for Potassium-Ion Batteries

Potassium-ion batteries (PIBs) are considered as a promising technology alternative to lithium-ion batteries due to more abundance of potassium than lithium and a lower redox potential of K/K⁺ than that of Na/Na⁺. The critical limitation in PIBs is the electrode with poor rate capability and cycling stability induced by the sluggish reaction kinetics and large volume change during potassiation and depotassiation. In this work, we report a turbostratic lattice iodine-doped carbon (TLIC) nanosheet as an advanced innovative anode for PIBs displaying fast charge/discharge and electrode stability. The turbostratic lattice caused by doping of large-sized iodine and the unique charge transfer between iodine/carbon atoms creates more active sites and a shorter transport distance for K ions, improves the electrochemical activity, promotes rapid ion diffusion, and enhances pseudocapacitive behavior. The TLIC exhibits a high capacity of 433.5 mAh g^-1 at 50 mA g^-1, an ultrahigh rate capability of 162.1 mAh g^-1 at 20 A g^-1, and an excellent capacity retention of ∼96% (206 mAh g^-1) after 4000 cycles. The combination of turbostratic lattice and pseudocapactive storage is an effective approach to designing carbon electrodes with the transformational performance of high capacity, rate performance, and long lifetime for practical applications of PIBs.

Sustainable Biomass-Derived Carbon Electrodes for Potassium and Aluminum Batteries: Conceptualizing the Key Parameters for Improved Performance

The development of sustainable, safe, low-cost, high energy and density power-density energy storage devices is most needed to electrify our modern needs to reach a carbon-neutral society by ~2050. Batteries are the backbones of future sustainable energy sources for both stationary off-grid and mobile plug-in electric vehicle applications. Biomass-derived carbon materials are extensively researched as efficient and sustainable electrode/anode candidates for lithium/sodium-ion chemistries due to their well-developed tailored textures (closed pores and defects) and large microcrystalline interlayer spacing and therefore opens-up their potential applications in sustainable potassium and aluminum batteries. The main purpose of this perspective is to brief the use of biomass residues for the preparation of carbon electrodes for potassium and aluminum batteries annexed to the biomass-derived carbon physicochemical structures and their aligned electrochemical properties. In addition, we presented an outlook as well as some challenges faced in this promising area of research. We believe that this review enlightens the readers with useful insights and a reasonable understanding of issues and challenges faced in the preparation, physicochemical properties and application of biomass-derived carbon materials as anodes and cathode candidates for potassium and aluminum batteries, respectively. In addition, this review can further help material scientists to seek out novel electrode materials from different types of biomasses, which opens up new avenues in the fabrication/development of next-generation sustainable and high-energy density batteries.

FeSb2 Nanoparticles Embedded in 3D Porous Carbon Framework: An Robust Anode Material for Potassium Storage with Long Activation Process

Due to their characteristics of high capacity and appropriate potassiation/depotassiation potential, Sb-based materials have become a class of promising anode materials for potassium ion batteries (PIBs). However, the huge strain induced by potassiation/depotassiation limits their ability to periodically accept/release K⁺ . Herein, a composite with FeSb₂ nanoparticles embedded in a 3D porous carbon framework (FeSb₂ @3DPC) is successfully constructed as an extremely stable anode material for PIBs. Benefiting from the synergistic effect of the design of nano and porous structures, the introduction of the inactive metal Fe, the firm anchoring of the FeSb₂ nanoparticles by the carbon material, and the incomplete reaction of the FeSb₂ , the FeSb₂ @3DPC can achieve an ultra-long cycle life of over 4000 cycles at a current density of 500 mA g^-1 . Furthermore, ex situ X-ray diffraction and transmission electron microscopy reveal a gradual activation process of FeSb₂ for potassium storage. Fortunately, after activation, the electrochemical polarization of the FeSb₂ @3DPC anode gradually alleviates and the capacitance-controlled charge storage mode further dominates compared with the diffusion-controlled mode, all of which promote the FeSb₂ @3DPC to maintain the stable potassium storage capability.

Robust high-temperature potassium-ion batteries enabled by carboxyl functional group energy storage

The popularly reported energy storage mechanisms of potassium-ion batteries (PIBs) are based on alloy-, de-intercalation-, and conversion-type processes, which inevitably lead to structural damage of the electrodes caused by intercalation/de-intercalation of K⁺ with a relatively large radius, which is accompanied by poor cycle stabilities. Here, we report the exploration of robust high-temperature PIBs enabled by a carboxyl functional group energy storage mechanism, which is based on an example of p-phthalic acid (PTA) with two carboxyl functional groups as the redox centers. In such a case, the intercalation/de-intercalation of K⁺ can be performed via surface reactions with relieved volume change, thus favoring excellent cycle stability for PIBs against high temperatures. As proof of concept, at the fixed working temperature of 62.5 °C, the initial discharge and charge specific capacities of the PTA electrode are ∼660 and 165 mA⋅h⋅g^-1, respectively, at a current density of 100 mA⋅g^-1, with 86% specific capacity retention after 160 cycles. Meanwhile, it delivers 81.5% specific capacity retention after 390 cycles under a high current density of 500 mA⋅g^-1 The cycle stabilities achieved under both low and high current densities are the best among those of high-temperature PIBs reported previously.

Biological enzyme treatment of starch-based lithium-ion battery silicon-carbon composite

Silicon/carbon composites have the disadvantages of large volume expansion and high cost, which limits their commercial application. In this study, green and economic starch was used to prepare porous starch (PS) under the action of enzymes, and then nano-silica was embedded in the PS. A PS based carbon/silicon/carbon composite was prepared by coating and carbonizing the starch slurry, which can alleviate the volume expansion of silicon. The results show that the anode composite material with 20% silicon content has a high initial capacity of 869 mAh g^-1 and an initial Coulombic efficiency of 66% at 0.2 A g^-1, and the specific capacity is maintained 450 mAh g^-1 after 100 cycles. When the silicon content reaches 30%, the reversible capacity of the composite is 1490 mAh g^-1 at a current density of 0.2 A g^-1, and the capacity remains 850 mAh g^-1 after 100 cycles. Its excellent properties and stability are attributed to the abundant porosity of the carbon in the starch derived layer, which improves the structural stability and electrochemical kinetics. This method provides a reference for the sustainable and environmental protection of lithium-ion battery anode materials.

Tuning the electronic conductivity of porous nitrogen-doped carbon nanofibers with graphene for high-performance potassium-ion storage

In the designed graphene/porous nitrogen-doped carbon nanofibers, graphene can improve the electronic conductivity of the composite materials, and a large amount of mesopores provided much more exposed N-doped active sites for adsorbing K⁺.