Functional materials for rechargeable batteries

Designing electrolytes with high solubility of sulfides/disulfides for high-energy-density and low-cost K-Na/S batteries

Alkaline metal sulfur (AMS) batteries offer a promising solution for grid-level energy storage due to their low cost and long cycle life. However, the formation of solid compounds such as M2S2 and M2S (M = Na, K) during cycling limits their performance. Here we unveil intermediate-temperature K-Na/S batteries utilizing advanced electrolytes that dissolve all polysulfides and sulfides (K2Sx, x = 1-8), significantly enhancing reaction kinetics, specific capacity, and energy density. These batteries achieve near-theoretical capacity (1655 mAh g-1 sulfur) at 75 °C with a 1 M sulfur concentration. At a 4 M sulfur concentration, they deliver 830 mAh g-1 at 2 mA cm-2, retaining 71% capacity after 1000 cycles. This new K-Na/S battery with specific energy of 150-250 Wh kg-1 only employs earth-abundant elements, making it attractive for long-duration energy storage.

Beyond Catalysts: Exploring Discharge Product Growth and Intrinsic Overpotential in Lithium-Oxygen Batteries

The lithium-oxygen (Li-O2) battery, renowned for its exceptionally high theoretical energy density, is poised to revolutionize next-generation energy storage systems. However, its practical application depends on overcoming several challenges, particularly the high cathode overpotential, which significantly diminishes the battery's energy efficiency and durability. This study delves into the interactions at the cathode surface during oxygen reduction and evolution reactions (ORR/OER), extending the analysis beyond the initial reaction stages to encompass the extensive charge-discharge process. We introduce and define the concepts of intrinsic equilibrium potential and intrinsic overpotential, demonstrating that these critical parameters are predominantly influenced by the growth of discharge products, rather than the catalysts, thereby underscoring the inherent properties of the battery. This shift in focus from merely enhancing cathode catalysts to understanding and leveraging the intrinsic characteristics of the battery discharge process opens new avenues for optimizing and enhancing the performance of large-scale Li-O2 batteries. Furthermore, our findings indicate potential broader applications to other metal-oxygen systems, paving the way for the design of high-capacity, high-efficiency energy storage technologies.

Gradient Lithium Ion Regulation Current Collectors for High-Performance and Dendrite-Free Li Metal Batteries

Lithium metal anode has attracted wide attention due to its ultrahigh theoretical specific capacity, lowest reduction potential, and low density. However, uncontrollable dendritic growth and volume change caused by uneven Li+ deposition still seriously hinder the large-scale commercial application of lithium metal batteries, even causing serious battery explosions and other safety problems. Hence, gold nanoparticles with a gradient distribution anchored on 3D carbon fiber paper (CP) current collectors followed by the encapsulation of polydopamine (PDA) (CP/Au/PDA) are constructed for stable and dendrite-free Li metal anodes for the first time. Significantly, lithiophilic Au nanoparticles showing a gradient distribution in the carbon fiber paper could guide the transfer of Li+ from the outside to the inside of the CP/Au/PDA electrode as well as lower the nucleation overpotential of Li, thereby obtaining the uniform Li deposition. Meanwhile, the PDA layer could in situ be converted to Li-PDA which could serve as an efficient Li+ conductor to further facilitate uniform Li+ transport among the whole CP/Au/PDA electrode. Besides, 3D carbon fiber paper could effectively accommodate the volume change during the plating/stripping process of Li metal. As a result, CP/Au/PDA electrodes deliver a low nucleation overpotential (∼9 mV) and a high Coulombic efficiency (mean value of ∼98.8%) at a current density of 1 mA cm-2 with the capacity of 1 mA h cm-2. Furthermore, Li@CP/Au/PDA electrodes also can demonstrate an ultralow voltage hysteresis (∼20 mV) and a long cycle life (1000 h) in symmetric cells. Finally, with LiFePO4 (LFP) as the cathode, the Li@CP/Au/PDA-LFP full cell delivers a high discharge capacity of 136 mA h g-1 even after 350 cycles at 1C, exhibiting a per cycle loss as low as 0.01%. This gradient lithium ion regulation current collector is of great significance for the development of lithium metal anodes.

Microstructure tuned Na3V2(PO4)3@C electrodes toward ultra-long-life sodium-ion batteries

Sodium-ion batteries (SIBs) are emerging as the best replacement for Li-ion batteries. In this regard, research on developing a reliable cathode material for SIBs is burgeoning. Rhombohedral Na3V2(PO4)3 (NVP), is a typical sodium super ionic conductor (NASICON) type material having prominent usage as a cathode material for SIBs. In this study, we prepared an NVP@C composite using a one-step hydrothermal method (at 180 °C) and consecutively calcined at different temperatures (750, 800, 850, and 900 °C). All the samples were thoroughly characterized and the changes in the crystal structure and particle size distribution were investigated using a Rietveld refinement method. NVP calcined at 850 °C exhibits the best battery performance with a discharge capacity of 94 mA h g-1 and retention up to 90% after 250 cycles at 2C. It also exhibits remarkable cycling stability with 94% (63 mA h g-1) retention after 2000 cycles at high-rate endurance (10C). The observed electrochemical performances of the samples were correlated with improved electrical conductivity due to the conductive carbon mixing with Na3V2(PO4)3 and enhancement in the crystallinity.

The Promising Potential of Gallium Based Liquid Metals for Energy Storage

Energy storage devices play a crucial role in various applications, such as powering electronics, power backup for homes and businesses, and support for the integration of renewable energy sources into electrical grid applications. Electrode materials for energy storage devices are preferred to have a flexible nature, conductive, better capacity, and low-toxicity. Using Gallium based liquid metal alloys, such as Eutectic Gallium-Indium (EGaIn), Eutectic Gallium-Tin (EGaSn), and Eutectic Gallium-Indium-Tin (EGaInSn), as electrode materials play very important role in energy storage devices. These liquid metals have some interesting properties with a self-healing nature, high mechanical stability, compatibility with various materials, fluidity, low young's modulus, high electrical and thermal conductivity. Those properties have made it suitable to be used in various energy storage devices. In this mini review, we have concisely described the advantages and challenges of using liquid metal as electrode materials for various energy storage devices.

Rational Design of Flexible, Self-Supporting, and Binder-Free Prussian White/KetjenBlack/MXene Composite Electrode for Sodium-Ion Batteries with Boosted Electrochemical Performance

Due to their cost-effectiveness, abundant resources, and suitable working potential, sodium-ion batteries are anticipated to establish themselves as a leading technology in the realm of grid energy storage. However, sodium-ion batteries still encounter challenges, including issues related to low energy density and constrained cycling performance. In this study, a self-supported electrode composed of Prussian white/KetjenBlack/MXene (TK-PW) is proposed. In the TK-PW electrode, the MXene layer is coated with Prussian white nanoparticles and KetjenBlack with high conductivity, which is conducive to rapid Na+ dynamics and effectively alleviates the expansion of the electrode. Notably, the electrode preparation method is uncomplicated and economically efficient, enabling large-scale production. Electrochemical testing demonstrates that the TK-PW electrode retains 74.9% of capacity after 200 cycles, with a discharge capacity of 69.7 mAh·g-1 at 1000 mA·g-1. Furthermore, a full cell is constructed, employing a hard carbon anode and TK-PW cathode to validate the practical application potential of the TK-PW electrode.

The Mechanism of Inhomogeneous Mass Transfer Process of Separators in Lithium-Ion Batteries

The liquid-phase mass transport is the key factor affecting battery stability. The influencing mechanism of liquid-phase mass transport in the separators is still not clear, the internal environment being a complex multi-field during the service life of lithium-ion batteries. The liquid-phase mass transport in the separators is related to the microstructure of the separator and the physicochemical properties of electrolytes. Here, in-situ local electrochemical impedance spectra were developed to investigate local inhomogeneities in the mass transfer process of lithium-ion batteries. The geometric microstructure of the separator significantly impacts the mass transfer process, with a reduction in porosity leading to increased overpotentials. A competitive relationship among porosity, tortuosity, and membrane thickness in the geometric parameters of the separator were established, resulting in a peak of polarization. The resistance of the liquid-phase mass transfer process is positively correlated with the viscosity of the electrolyte, hindering ion migration due to high viscosity. Polarization is closely related to the electrochemical performance, so a phase diagram of battery performance and inhomogeneous mass transfer was developed to guide the design of the battery. This study provides a foundation for the development of high stability lithium-ion batteries.

Recent advances in Zr and Hf-based MXenes and their hetero-structure as novel anode materials for Ca-ion batteries: theoretical insights from DFT approach

Recently, MXenes have been widely investigated for use as electrodes in various ion storage batteries. In this study, Zr2N, Hf2N and ZrHfN were explored as potential anode materials for Ca-ion batteries. AIMD simulations predict higher structural stability for our proposed MXenes at a temperature of 300 K. The adsorption energies at the most favourable adsorption sites are 1.31, 1.33 and 1.27 eV for Zr2N, Hf2N and ZrHfN, respectively. During the adsorption process, a significant amount of charge transfer occurs from the Ca atom to the nanosheets. DOS and PDOS analyses reveal that the adsorption of Ca atoms enhances the conductivity of the nanosheets. Moreover, the low diffusion barriers are found to be 0.076, 0.073 and 0.097 eV when the Ca atom migrates from its favourable adsorption site to a nearby site on Zr2N, Hf2N and ZrHfN nanosheets, resulting in high charging rates. The theoretical capacities of Zr2N, Hf2N and ZrHfN nanosheets are 1034, 561 and 707 mA h g-1, respectively. All the results from this study suggest that our proposed nanosheets can be potential anode materials for Ca-ion batteries. Among them, the Zr2N nanosheet shows superior anodic properties for Ca-ion batteries, which is also confirmed by specific capacity, diffusion barrier and open circuit voltage calculations.

A competitive-type photoelectrochemical aptasensor for 17 beta-estradiol detection in microfluidic devices based on a novel Au@Cd:SnO2/SnS2 nanocomposite

A competitive-type photoelectrochemical (PEC) aptasensor coupled with a novel Au@Cd:SnO2/SnS2 nanocomposite was designed for the detection of 17β-estradiol (E2) in microfluidic devices. The designed Au@Cd:SnO2/SnS2 nanocomposites exhibit high photoelectrochemical activity owing to the good matching of cascade band-edge and the efficient separation of photo-generated e-/h+ pairs derived from the Cd-doped defects in the energy level. The Au@Cd:SnO2/SnS2 nanocomposites were loaded into carbon paste electrodes (CPEs) to immobilize complementary DNA (cDNA) and estradiol aptamer probe DNA (E2-Apt), forming a double-strand DNA structure on the CPE surface. As the target E2 interacts with the double-strand DNA, E2-Apt is sensitively released from the CPE, subsequently increasing the photocurrent intensity due to the reduced steric hindrance of the electrode surface. The competitive-type sensing mechanism, combined with high PEC activity of the Au@Cd:SnO2/SnS2 nanocomposites, contributed to the rapid and sensitive detection of E2 in a "signal on" manner. Under the optimized conditions, the PEC aptasensor exhibited a linear range from 1.0 × 10-13 mol L-1 to 3.2 × 10-6 mol L-1 and a detection limit of 1.2 × 10-14 mol L-1 (S/N = 3). Moreover, the integration of microfluidic device with smartphone controlled portable electrochemical workstation enables the on-site detection of E2. The small sample volume (10 µL) and short analysis time (40 min) demonstrated the great potential of this strategy for E2 detection in rat serum and river water. With these advantages, the PEC aptasensor can be utilized for point-of-care testing (POCT) in both clinical and environmental applications.

Effect of sucrose-based carbon foams as negative electrode additive on the performance of lead-acid batteries under high-rate partial-state-of-charge condition

Lead-acid batteries are noted for simple maintenance, long lifespan, stable quality, and high reliability, widely used in the field of energy storage. However, during the use of lead-acid batteries, the negative electrode is prone to irreversible sulfation, failing to meet the requirements of new applications such as maintenance-free hybrid vehicles and solar energy storage. In this study, in order to overcome the sulfation problem and improve the cycle life of lead-acid batteries, active carbon (AC) was selected as a foaming agent and foam fixing agent, and carbon foams (CF) with layered porous structure was prepared by mixing with molten sucrose. Sucrose as raw material is green and cheap, and the material preparation process is simple. The prepared CF material was then added as an additive to the negative electrode plate, and the electrochemical performance of the electrode plate and the battery was studied. The results proved that the addition of CF could effectively inhibit the sulfate formation of the negative electrode plate, with the 1.0 % CF negative electrode plate showing the best electrochemical performance. Specifically, according to the result of battery cycle testing, the simulated battery with CF had a cycle life of 3642 times, which was 2.87 times that of the blank group and 2.39 times of the AC group. Meanwhile, rate testing showed that the simulated battery with CF could maintain a high capacity even under high-rate discharge conditions.

A Perspective of Bioinspired Interfaces Applied in Renewable Energy Storage and Conversion Devices

The natural world renders a large number of opportunities to design intriguing structures and fascinating functions for innovations of advanced surfaces and interfaces. Currently, bioinspired interfaces have attracted much attention in practical applications of renewable energy storage and conversion devices including rechargeable batteries, fuel cells, dye-sensitized solar cells, and supercapacitors. By mimicking miscellaneous natural creatures, many novel bioinspired interfaces with various components, structures, morphology, and configurations are exerted on the devices' electrodes, electrolytes, additives, separators, and catalyst matrixes, resorting to their wonderful mechanical, optical, electrical, physical, chemical, and electrochemical features compared with the corresponding traditional modes. In this Perspective, the principles of designing bioinspired interfaces are discussed with respect to biomimetic chemical components, physical morphologies, biochemical reactions, and macrobiomimetic assembly configurations. A brief summary, subsequently, is mainly focused on the recent progress on bioinspired interfaces applied in key materials for rechargeable batteries. Ultimately, a critical comment is projected on significant opportunities and challenges existing in the future development course of bioinspired interfaces. It is expected that this Perspective is able to provide a profound perception into some underlying artificial intelligent energy storage and conversion device design as a promising candidate to resolve the global energy crisis and environmental pollution.

New Emerging Fast Charging Microscale Electrode Materials

Fast charging lithium (Li)-ion batteries are intensively pursued for next-generation energy storage devices, whose electrochemical performance is largely determined by their constituent electrode materials. While nanosizing of electrode materials enhances high-rate capability in academic research, it presents practical limitations like volumetric packing density and high synthetic cost. As an alternative to nanosizing, microscale electrode materials cannot only effectively overcome the limitations of the nanosizing strategy but also satisfy the requirement of fast-charging batteries. Therefore, this review summarizes the new emerging microscale electrode materials for fast charging from the commercialization perspective. First, the fundamental theory of electronic/ionic motion in both individual active particles and the whole electrode is proposed. Then, based on these theories, the corresponding optimization strategies are summarized toward fast-charging microscale electrode materials. In addition, advanced functional design to tackle the mechanical degradation problems related to next generation high capacity alloy- and conversion-type electrode materials (Li, S, Si et al.) for achieving fast charging and stable cycling batteries. Finally, general conclusions and the future perspective on the potential research directions of microscale electrode materials are proposed. It is anticipated that this review will provide the basic guidelines for both fundamental research and practical applications of fast-charging batteries.

Extending Cycling Life Beyond 300 000 Cycles in Aqueous Zinc Ion Capacitors Through Additive Interface Engineering

Developing low-cost and long-cycling-life aqueous zinc (Zn) ion capacitors (AZICs) for large-scale electrochemical energy storage still faces the challenges of dendritic Zn deposition and interfacial side reactions. Here, an interface engineering strategy utilizing a dibenzenesulfonimide (BBI) additive is employed to enhance the stability of the Zn metal anode/electrolyte interface. The first-principles calculation results demonstrate that BBI anions can be chemically adsorbed on Zn metal. Meanwhile, the experimental results confirm that the BBI-Zn interfacial layer converts the original water-richelectric double layer (EDL) into a water-poor EDL, effectively inhibiting the water related parasitic reaction at the electrode/electrolyte interface. In addition, the BBI-Zn interfacial layer introduces an additional Zn ions (Zn2+) migration energy barrier, increasing the Zn2+ de-solvation activation energy, consequently raising the Zn2+ nucleation overpotential, and thus achieving the compact and uniform Zn deposition behavior. Furthermore, the solid electrolyte interphase (SEI) layer derived from the BBI-Zn interfacial layer during cycling can further maintain the interfacial stability of the Zn anode. Owing to the above favorable features, the assembled AZIC exhibits an ultra-long cycling life of over 300 000 cycles based on the additive engineering strategy, which shows application prospects in high-performance AZICs.

Carbon-coated Ni0.5Mg0.5Fe1.7Mn0.3O4 nanoparticles as a novel anode material for high energy density lithium-ion batteries

Lithium-ion batteries (LIBs) have gained considerable attention from the scientific community due to their outstanding properties, such as high energy density, low self-discharge, and environmental sustainability. Among the prominent candidates for anode materials in next-generation LIBs are the spinel ferrites, represented by the MFe2O4 series, which offer exceptional theoretical capacities, excellent reversibility, cost-effectiveness, and eco-friendliness. In the scope of this study, Ni0.5Mg0.5Fe1.7Mn0.3O4 nanoparticles were synthesized using a sol-gel synthesis method and subsequently coated with a carbon layer to further enhance their electrochemical performance. TEM images confirmed the presence of the carbon coating layer on the Ni0.5Mg0.5Fe1.7Mn0.3O4/C composite. The analysis of the measured X-ray diffraction (XRD) and Raman spectroscopy results confirmed the formation of nanocrystalline Ni0.5Mg0.5Fe1.7Mn0.3O4 before coating and amorphous carbon in the Ni0.5Mg0.5Fe1.7Mn0.3O4/C after the coating. The Ni0.5Mg0.5Fe1.7Mn0.3O4 anode material exhibited a much higher specific capacity than the traditional graphite material, with initial discharge/charge capacities of 1275 and 874 mA h g-1, respectively, at a 100 mA g-1 current density and a first coulombic efficiency of 68.54%. The long-term cycling test showed a slight capacity fading, retaining approximately 85% of its initial capacity after 75 cycles. Notably, the carbon-coating layer greatly enhanced the stability and slightly increased the capacity of the as-prepared Ni0.5Mg0.5Fe1.7Mn0.3O4. The first discharge/charge capacities of Ni0.5Mg0.5Fe1.7Mn0.3O4/C at 100 mA g-1 current density reached 1032 and 723 mA h g-1, respectively, and a first coulombic efficiency of 70.06%, with an increase of discharge/charge capacities to 826.6 and 806.2 mA h g-1, respectively, after 75 cycles (with a capacity retention of 89.7%), and a high-rate capability of 372 mA h g-1 at 2C. Additionally, a full cell was designed using a Ni0.5Mg0.5Fe1.7Mn0.3O4/C anode and an NMC811 cathode. The output voltage was about 2.8 V, with a high initial specific capacity of 755 mA h g-1 at 0.125C, a high rate-capability of 448 mA h g-1 at 2C, and a high-capacity retention of 91% after 30 cycles at 2C. The carbon coating layer on Ni0.5Mg0.5Fe1.7Mn0.3O4 nanoparticles played a crucial role in the excellent electrochemical performance, providing conducting, buffering, and protective effects.

Architectural design of anode materials for superior alkali-ion (Li/Na/K) batteries storage

Developing high-performance anode materials remains a significant challenge for clean energy storage systems. Herein, we investigated the (MXene/MoSe2@C) heterostructure hybrid nanostructure as a superior anode material for application in lithium, sodium, and potassium ion batteries (LIBs, SIBs, and PIBs). Moreover, the anode structure's stability was examined via the open-source Large-scale atomic/molecular massively Parallel Simulator code. Our results indicated that the migration of SIBs toward the anode material is significantly greater than other ions during charge and discharge cycles. Therefore, SIBs systems can be competitive with PIBs and LIBs systems. In addition, the average values of the potential energies for the anode materials/ions complexes are about ~ - 713.65, ~  - 2030.41, and ~ - 912.36 kcal mol-1 in systems LIBs, SIBs, and PIBs, respectively. This study provides a rational design strategy to develop high-performance anode materials in SIBs/PIBs/LIBs systems, which can be developed for other transition metal chalcogenide-based composites as a superior anode of alkali metal ion battery storage systems.

Modelling structure and ionic diffusion in a class of ionic liquid crystal-based solid electrolytes

Next-generation high-efficiency Li-ion batteries require an electrolyte that is both safe and thermally stable. A possible choice for high performance all-solid-state Li-ion batteries is a liquid crystal, which possesses properties in-between crystalline solids and isotropic liquids. By employing molecular dynamics simulations together with various experimental techniques, we have designed and analyzed a novel liquid crystal electrolyte composed of rigid naphthalene-based moieties as mesogenic units, grafted to flexible alkyl chains of different lengths. We have synthesized novel highly ordered lamellar phase liquid crystal electrolytes at 99% purity and have evaluated the effect of alkyl chain length variation on ionic conduction. We find that the conductivity of the liquid crystal electrolytes is directly dependent on the extent of the nanochannels formed by molecule self-organization, which itself depends non-monotonously on the size of the alkyl chains. In addition, we show that the ion pair interaction between the anionic center of the liquid crystal molecules and the Li+ ions plays a crucial role in the overall conductivity. Based on our results, we suggest that further improvement of the ionic conductivity performance is possible, making this novel family of liquid crystal electrolytes a promising option for the design of entirely solid-state Li+ ion batteries.

Copper tetrathiovanadate (Cu3VS4): a newly emerging electrode for rechargeable aqueous aluminum-ion batteries

We report the electrochemistry of Al3+ ion storage in copper tetrathiovanadate (Cu3VS4) in an aqueous electrolyte for the first time. It is found that Cu3VS4 could deliver an initial discharge capacity of 111 mA h g-1 at a current rate of 0.5 A g-1 and 77 mA h g-1 up to the 300th cycle at 2 A g-1 along with an excellent rate capability. The better electrochemical performance may be attributed to the high theoretical capacity of sulfur and the superior conductivity of copper which allows facile Al3+ ion diffusion in Cu3VS4. The electrochemical mechanism of Al3+ ion storage is also illustrated.

A new Mn-based layered cathode with enlarged interlayer spacing for potassium ion batteries

Layered Mn-based cathode (KxMnO2) has attracted wide attention for potassium ion batteries (PIBs) because of its high specific capacity and energy density. However, the structure and capacity of KxMnO2 cathode are constantly degraded during the cycling due to the strong Jahn-Teller effect of Mn3+ and huge ionic radius of K+. In this work, lithium ion and interlayer water were introduced into Mn layer and K layer in order to suppress the Jahn-Teller effect and expand interlayer spacing, respectively, thus obtaining new types of K0.4Mn1-xLixO2·0.33H2O cathode materials. The interlayer spacing of the K0.4MnO2 increased from 6.34 to 6.93 Å after the interlayer water insertion. X-ray photoelectron spectroscopy studies demonstrated that proper lithium doping can effectively control the ratio of Mn3+/Mn4+ and inhibit the Jahn-Teller effect. In-situ X-ray diffraction exhibited that lithium doping can inhibit the irreversible phase transition and improve the structural stability of materials during cycling. As a result, the optimal K0.4Mn0.9Li0.1O2·0.33H2O not only delivered a higher capacity retention of 84.04 % compared to the value of 28.09 % for K0.4MnO2·0.33H2O, but also maintained a greatly enhanced rate capability. This study provides a new opportunity for designing layered manganese-based cathode materials with high performance for PIBs.

Uniting Young's modulus and the flexibility of solid-state electrolytes for high-performance Li-batteries at room temperature

The use of solid-state composite electrolytes is a promising strategy to advance all-solid-state batteries. Great efforts have been devoted to improving the ionic conductivity of electrolytes, while little attention has been paid to studying the effect of their mechanical properties on electrochemical performance. The Young's modulus and flexibility are two important and contrary mechanical properties co-existing in electrolytes. Their effect on the electrochemical performance of all-solid-state batteries is important. Here, we study the effect of Young's modulus and flexibility based on a designed sandwich-structured solid-state composite electrolyte (SSCE) with high ionic conductivity (4.57 × 10-4 S cm-1 at 25 °C). In the SSCE, the middle layer with 9 : 1 : 0.5 mass ratio of Li6.4La3Zr1.4Ta0.6O12, poly(vinylidene fluoride-co-hexafluoropropylene) and bis(trifluoromethane)sulfonimide lithium is sandwiched by two outer layers with a 0.1 : 1 : 0.5 mass ratio among them, which can effectively suppress lithium dendrites and have intimate contact with the electrodes, leading to Li|SSCE|LiFePO4 with promising rate performance (155.5 mA h g-1 at 0.05 C and 124.4 mA h g-1 at 1 C) and excellent cycling stability with 98.8% capacity retention after 450 cycles at 25 °C. This work demonstrates that all-solid-state batteries have greatly enhanced electrochemical performance by uniting Young's modulus and flexibility via SSCEs, and provides a feasible strategy for the development of all-solid-state batteries.

Engineering Strategies for Suppressing the Shuttle Effect in Lithium-Sulfur Batteries

Lithium-sulfur (Li-S) batteries are supposed to be one of the most potential next-generation batteries owing to their high theoretical capacity and low cost. Nevertheless, the shuttle effect of firm multi-step two-electron reaction between sulfur and lithium in liquid electrolyte makes the capacity much smaller than the theoretical value. Many methods were proposed for inhibiting the shuttle effect of polysulfide, improving corresponding redox kinetics and enhancing the integral performance of Li-S batteries. Here, we will comprehensively and systematically summarize the strategies for inhibiting the shuttle effect from all components of Li-S batteries. First, the electrochemical principles/mechanism and origin of the shuttle effect are described in detail. Moreover, the efficient strategies, including boosting the sulfur conversion rate of sulfur, confining sulfur or lithium polysulfides (LPS) within cathode host, confining LPS in the shield layer, and preventing LPS from contacting the anode, will be discussed to suppress the shuttle effect. Then, recent advances in inhibition of shuttle effect in cathode, electrolyte, separator, and anode with the aforementioned strategies have been summarized to direct the further design of efficient materials for Li-S batteries. Finally, we present prospects for inhibition of the LPS shuttle and potential development directions in Li-S batteries.

Versatile Protein and Its Subunit Biomolecules for Advanced Rechargeable Batteries

Rechargeable batteries are of great significance for alleviating the growing energy crisis by providing efficient and sustainable energy storage solutions. However, the multiple issues associated with the diverse components in a battery system as well as the interphase problems greatly hinder their applications. Proteins and their subunits, peptides, and amino acids, are versatile biomolecules. Functional groups in different amino acids endow these biomolecules with unique properties including self-assembly, ion-conducting, antioxidation, great affinity to exterior species, etc. Besides, protein and its subunit materials can not only work in solid forms but also in liquid forms when dissolved in solutions, making them more versatile to realize materials engineering via diverse approaches. In this review, it is aimed to offer a comprehensive understanding of the properties of proteins and their subunits, and research progress of using these versatile biomolecules to address the engineering issues of various rechargeable batteries, including alkali-ion batteries, lithium-sulfur batteries, metal-air batteries, and flow batteries. The state-of-the-art advances in electrode, electrolyte, separator, binder, catalyst, interphase modification, as well as recycling of rechargeable batteries are involved, and the impacts of biomolecules on electrochemical properties are particularly emphasized. Finally, perspectives on this interesting field are also provided.

Enhanced electrochemical performances based on ZnSnO3 microcubes functionalized in-doped carbon nanofibers as free-standing anode materials

The binary composite, ZnSnO3 microcubes (ZSO MC) homogeneously parceled in an N-doped carbon nanofiber membrane (ZSO@CNFM), was synthesized via a mild hydrothermal, electrospinning and carbonization process as a flexible lithium-ion battery (LIB) anode material. The unique carbon-coating layer architecture of ZSO@CNFM not only plays a crucial role in alleviating the volume change of ZSO MC during lithium ion insertion/extraction processes, but also constructs a three-dimensional (3D) transport network with the help of interconnected carbon nanofibers (CNFs) to ensure the structural integrity of the material and promote the electrochemical reaction kinetics. Due to its good flexibility characteristics, the as-prepared ZSO@CNFM can be directly adopted as an anode material for LIBs without the use of copper foil, conductive carbon black and any binder. Electrochemical surveying results manifest that the optimal ZSO@CNFM electrode displays excellent cycling stability (582.6 mA h g-1 after 100 lithiation/delithiation cycles at 100 mA g-1), high coulombic efficiency (CE, 99.6% at 100th cycles), and superior rate performance (349.5 mA h g-1 at 2 A g-1). The good electrochemical properties can be ascribed to the synergistic effect of the high theoretical specific capacity of ZSO MC, favourable stability of the carbon substrate, the open structure of ZSO@CNFM and the 3D continuous highly conductive framework for rapid electron/ion transfer.

Boosting Lean Electrolyte Lithium-Sulfur Battery Performance with Transition Metals: A Comprehensive Review

Lithium-sulfur (Li-S) batteries have received widespread attention, and lean electrolyte Li-S batteries have attracted additional interest because of their higher energy densities. This review systematically analyzes the effect of the electrolyte-to-sulfur (E/S) ratios on battery energy density and the challenges for sulfur reduction reactions (SRR) under lean electrolyte conditions. Accordingly, we review the use of various polar transition metal sulfur hosts as corresponding solutions to facilitate SRR kinetics at low E/S ratios (< 10 µL mg-1), and the strengths and limitations of different transition metal compounds are presented and discussed from a fundamental perspective. Subsequently, three promising strategies for sulfur hosts that act as anchors and catalysts are proposed to boost lean electrolyte Li-S battery performance. Finally, an outlook is provided to guide future research on high energy density Li-S batteries.

Recent Progress on Honeycomb Layered Oxides as a Durable Cathode Material for Sodium-Ion Batteries

Sodium-ion batteries (SIBs) are becoming promising candidates for energy storage devices due to the low cost, abundant reserves, and excellent electrochemical performance. As the most important unit, layered cathodes attract much attention, where honeycomb-layered-oxides (HLOs) manifest outstanding structural stability, high redox potential, and long-life electrochemistry. Here, recent progress on HLOs as well as Na₃ Ni₂ SbO₆ and Na₃ Ni₂ BiO₆ as two representative materials are introduced, and the crystal and electronic structure, electrochemical performance, and modification strategies are summarized. The advanced high nickel HLOs are highlighted toward development of state-of-the-art sodium-ion batteries. This review would deepen the understanding of superstructure in layered oxides, as well as structure-property relationship, and inspire more interest in high output voltage, long lifespan sodium-ion batteries.

Transition metal chalcogenides for next-generation energy storage

Transition-metal chalcogenide nanostructures provide a unique material platform to engineer next-generation energy storage devices such as lithium-ion, sodium-ion, and potassium-ion batteries and flexible supercapacitors. The transition-metal chalcogenide nanocrystals and thin films have enhanced electroactive sites for redox reactions and hierarchical flexibility of structure and electronic properties in the multinary compositions. They also consist of more earth-abundant elements. These properties make them attractive and more viable new electrode materials for energy storage devices compared to the traditional materials. This review highlights the recent advances in chalcogenide-based electrodes for batteries and flexible supercapacitors. The viability and structure-property relation of these materials are explored. The use of various chalcogenide nanocrystals supported on carbonaceous substrates, two-dimensional transition metal chalcogenides, and novel MXene-based chalcogenide heterostructures as electrode materials to improve the electrochemical performance of lithium-ion batteries is discussed. The sodium-ion and potassium-ion batteries offer a more viable alternative to lithium-ion technology as they consist of readily available source materials. Application of various transition metal chalcogenides such as MoS2, MoSe2, VS2, and SnSx, composite materials, and heterojunction bimetallic nanosheets composed of multi-metals as electrodes to enhance the long-term cycling stability, rate capability, and structural strength to counteract the large volume expansion during the ion intercalation/deintercalation processes is highlighted. The promising performances of layered chalcogenides and various chalcogenide nanowire compositions as electrodes for flexible supercapacitors are also discussed in detail. The review also details the progress made in new chalcogenide nanostructures and layered mesostructures for energy storage applications.

Nanoscale Borate Coating Network Stabilized Iron Oxide Anode for High-Energy-Density Bipolar Lithium-Ion Batteries

High-capacity metal oxides based on non-toxic earth-abundant elements offer unique opportunities as advanced anodes for lithium-ion batteries (LIBs). But they often suffer from large volumetric expansion, particle pulverization, extensive side reactions, and fast degradations during cycling. Here, an easy synthesis method is reported to construct amorphous borate coating network, which stabilizes conversion-type iron oxide anode for the high-energy-density semi-solid-state bipolar LIBs. The nano-borate coated iron oxide anode has high tap density (1.6 g cm^-3 ), high capacity (710 mAh g^-1 between 0.5 - 3.0 V, vs Li/Li⁺ ), good rate performance (200 mAh g^-1 at 50 C), and excellent cycling stability (≈100% capacity resention over 1,000 cycles at 5 A g^-1 ). When paired with high-voltage cathode LiCoO₂ , it enables Cu current collector-free pouch-type classic and bipolar full cells with high voltage (7.6 V with two stack layers), achieving high energy density (≈350 Wh kg^-1 ), outstanding power density (≈6,700 W kg^-1 ), and extended cycle life (75% capacity retention after 2,000 cycles at 2 C), superior to the state-of-the-art high-power LIBs using Li₄ Ti₅ O₁₂ anode. The design and methodology of the nanoscale polyanion-like coating can be applied to other metal oxides electrode materials, as well as other electrochemical materials and devices.

Guest Ion-Dependent Reaction Mechanisms of New Pseudocapacitive Mg3 V4 (PO4 )6 /Carbon Composite as Negative Electrode for Monovalent-Ion Batteries

Polyanion-type phosphate materials, such as M₃ V₂ (PO₄ )₃ (M = Li/Na/K), are promising as insertion-type negative electrodes for monovalent-ion batteries including Li/Na/K-ion batteries (lithium-ion batteries (LIBs), sodium-ion batteries (SIBs), and potassium-ion batteries (PIBs)) with fast charging/discharging and distinct redox peaks. However, it remains a great challenge to understand the reaction mechanism of materials upon monovalent-ion insertion. Here, triclinic Mg₃ V₄ (PO₄ )₆ /carbon composite (MgVP/C) with high thermal stability is synthesized via ball-milling and carbon-thermal reduction method and applied as a pseudocapacitive negative electrode in LIBs, SIBs, and PIBs. In operando and ex situ studies demonstrate the guest ion-dependent reaction mechanisms of MgVP/C upon monovalent-ion storage due to different sizes. MgVP/C undergoes an indirect conversion reaction to form Mg⁰ , V⁰ , and Li₃ PO₄ in LIBs, while in SIBs/PIBs the material only experiences a solid solution with the reduction of V³⁺ to V²⁺ . Moreover, in LIBs, MgVP/C delivers initial lithiation/delithiation capacities of 961/607 mAh g^-1 (30/19 Li⁺ ions) for the first cycle, despite its low initial Coulombic efficiency, fast capacity decay for the first 200 cycles, and limited reversible insertion/deinsertion of 2 Na⁺ /K⁺ ions in SIBs/PIBs. This work reveals a new pseudocapacitive material and provides an advanced understanding of polyanion phosphate negative material for monovalent-ion batteries with guest ion-dependent energy storage mechanisms.

Charge fluctuation drives anion rotation to enhance the conductivity of Na11M2PS12 (M = Si, Ge, Sn) superionic conductors

Solid superionic conductors exhibit good battery safety and stability, promising to replace organic liquid electrolytes. However, a comprehensive understanding of the factors determining high ion mobility remains elusive. Experiments have confirmed that the Na₁₁Sn₂PS₁₂ superionic conductor has high room temperature Na⁺-ion conductivity; excellent phase stability has been demonstrated in a solid-state electrolyte. The PS₄ anion rotation exists in Na₁₁M₂PS₁₂-type superionic conductors, but this rotation is affected by the isovalent cation substitutions of the M site. In combination with ab initio molecular dynamic simulations and joint time correlation analysis of the AIMD data, we show that the transport of Na⁺ ions is directly enhanced by the charge fluctuation in their tetrahedral MS₄ anions that comprise the framework. The fundamental reason for the charge fluctuation is the material structure forming a micro-parallel capacitor with MS₄ anions, which governs the differential capacitance. Our study provides a fundamental and comprehensive understanding of the structure-controlled charge transfer of Na₁₁M₂PS₁₂-type material and can guide solid-state battery optimization and design.

Effect of LLZO on the in situ polymerization of acrylate solid-state electrolytes on cathodes

The comprehensive performance of the state-of-the-art solid-state electrolytes (SSEs) cannot match the requirements of commercial applications, and constructing an organic-inorganic composite electrolyte in situ on a porous electrode is an effective coping strategy. However, there are few studies focused on the influence of inorganic ceramics on the polymerization of multi-organic components. In this study, it was found that the addition of Li_6.4La₃Zr_1.4Ta_0.6O₁₂ (LLZO) weakens the interaction between different polymers and makes organic and inorganic components contact directly in the solid electrolyte. These suppress the segregation of components in the in situ polymerized composite SSE, leading to a decrease in the polymer crystallization and improvement of electrolyte properties such as electrochemical stability window and mechanical properties. The composite solid-state electrolyte can be in situ constructed on different porous electrodes, which can establish close contact with active material particles, showing an ionic conductivity 4.4 × 10^-5 S cm^-1 at 25 °C, and afford the ternary cathode stability for 100 cycles.

2D Materials Boost Advanced Zn Anodes: Principles, Advances, and Challenges

Aqueous zinc-ion battery (ZIB) featuring with high safety, low cost, environmentally friendly, and high energy density is one of the most promising systems for large-scale energy storage application. Despite extensive research progress made in developing high-performance cathodes, the Zn anode issues, such as Zn dendrites, corrosion, and hydrogen evolution, have been observed to shorten ZIB's lifespan seriously, thus restricting their practical application. Engineering advanced Zn anodes based on two-dimensional (2D) materials are widely investigated to address these issues. With atomic thickness, 2D materials possess ultrahigh specific surface area, much exposed active sites, superior mechanical strength and flexibility, and unique electrical properties, which confirm to be a promising alternative anode material for ZIBs. This review aims to boost rational design strategies of 2D materials for practical application of ZIB by combining the fundamental principle and research progress. Firstly, the fundamental principles of 2D materials against the drawbacks of Zn anode are introduced. Then, the designed strategies of several typical 2D materials for stable Zn anodes are comprehensively summarized. Finally, perspectives on the future development of advanced Zn anodes by taking advantage of these unique properties of 2D materials are proposed.

Sacrificial Catalyst of Carbothermal-Shock-Synthesized 1T-MoS2 Layers for Ultralong-Lifespan Seawater Battery

A Pt-nanoparticle-decorated 1T-MoS₂ layer is designed as a sacrificial electrocatalyst by carbothermal shock (CTS) treatment to improve the energy efficiency and lifespan of seawater batteries. The phase transition of MoS₂ crystals from 2H to metallic 1T─induced by the simple but potent CTS treatment─improves the oxygen-reduction-reaction (ORR) activity in seawater catholyte. In particular, the MoS₂-based sacrificial catalyst effectively decreases the overpotential during charging via edge oxidation of MoS₂, enhancing the cycling stability of the seawater battery. Furthermore, Pt nanoparticles are deposited onto CTS-MoS₂ via an additional CTS treatment. The resulting specimen exhibits a significantly low charge/discharge potential gap of Δ0.39 V, high power density of 6.56 mW cm^-2, and remarkable cycling stability up to ∼200 cycles (∼800 h). Thus, the novel strategy reported herein for the preparation of Pt-decorated 1T-MoS₂ by CTS treatment could facilitate the development of efficient bifunctional electrocatalysts for fabricating seawater batteries with long service life.

Hydrogenated Amorphous Silicon-Based Nanomaterials as Alternative Electrodes to Graphite for Lithium-Ion Batteries

Graphite is the material most used as an electrode in commercial lithium-ion batteries. On the other hand, it is a material with low energy capacity, and it is considered a raw critical material given its large volume of use. In the current energy context, we must promote the search for alternative materials based on elements that are abundant, sustainable and that have better performance for energy storage. We propose thin materials based on silicon, which has a storage capacity eleven times higher than graphite. Nevertheless, due to the high-volume expansion during lithiation, it tends to crack, limiting the life of the batteries. To solve this problem, hydrogenated amorphous silicon has been researched, in the form of thin film and nanostructures, since, due to its amorphous structure, porosity and high specific surface, it could better absorb changes in volume. These thin films were grown by plasma-enhanced chemical vapor deposition, and then the nanowires were obtained by chemical etching. The compositional variations of films deposited at different temperatures and the incorporation of dopants markedly influence the stability and longevity of batteries. With these optimized electrodes, we achieved batteries with an initial capacity of 3800 mAhg^-1 and 82% capacity retention after 50 cycles.

Zero-Strain Insertion Anode Material of Lithium-Ion Batteries

The insertion type materials are the most important anode materials for lithium-ion batteries, but their insufficient capacity is the bottleneck of practical application. Here, LiAl₅ O₈ nanowires with high theoretical capacity and Li-ions diffusion coefficient are prepared and studied as an insertion anode material, which exhibits zero-strain properties upon electrochemical cycling. However, the poor electronic conductivity of LiAl₅ O₈ definitely sacrifices the capacity and limits the rate performance. Therefore, compact LiAl₅ O₈ and carbon composite are further synthesized, in which nanosized LiAl₅ O₈ particles are uniformly embedded in an amorphous carbon matrix. It displays a reversible capacity of 490.9 mAh g^-1 at 1 A g^-1 , and the capacity rises continuously to 996.8 mAh g^-1 after 1000 cycles due to the interfacial storage mechanism, that the excess Li⁺ ions can be accommodated in the grain boundaries and C/LiAl₅ O₈ interfaces.

Electrochemical recycling of homogeneous catalysts

Homogeneous catalysts have rapid kinetics and keen reaction selectivity. However, their widespread use for industrial catalysis has remained limited because of challenges in reusability. Here, we propose a redox-mediated electrochemical approach for catalyst recycling using metallopolymer-functionalized electrodes for binding and release. The redox platform was investigated for the separation of key platinum and palladium homogeneous catalysts used in organic synthesis and industrial chemical manufacturing. Noble metal catalysts for hydrosilylation, silane etherification, Suzuki cross-coupling, and Wacker oxidation were recycled electrochemically. The redox electrodes demonstrated high sorption uptake for platinum-based catalysts (Q_max up to 200 milligrams of platinum per gram of adsorbent) from product mixtures, with up to 99.5% recovery, while retaining full catalytic activity over multiple cycles. The combination of mechanistic studies and electronic structure calculations indicate that selective interactions with anionic intermediates during the catalytic cycle played a key role in the separations. Last, continuous flow cell studies support the scalability and favorable technoeconomics of electrochemical recycling.

Synthesis of Optically and Redox Active Polyenaminones from Diamines and α,α'-Bis[(dimethylamino)methylidene]cyclohexanediones

New oligo- and polyenaminones with M_w ~ 7-50 KDa were prepared in high yields by transaminative amino-enaminone polymerization of regioisomeric bis[(dimethylamino)methylidene]cyclohexanediones with alkylene and phenylenediamines. The polymers obtained are practically insoluble in aqueous and organic solvents and exhibit film-forming properties, UV light absorption at wavelengths below 500 nm, and redox activity. These properties indicate a promising application potential of these polymers, which could find use in optical and optoelectronic applications and in energy storage devices.

Ultrahigh Lithium Storage Capacity of Al2C Monolayer in a Restricted Multilayered Growth Mechanism

Designing anode materials with high lithium specific capacity is crucial to the development of high energy density lithium (ion) batteries. Herein, a distinctive lithium growth mechanism, namely, the restricted multilayered growth for lithium, and a strategy for lithium storage are proposed to achieve a balance between ultrahigh specific capacity and the need to avert uncontrolled dendritic growth of lithium. In particular, based on first-principles computation, we show that the Al₂C monolayer with a planar tetracoordinate carbon structure can be an ideal platform for realizing the restricted multilayered growth mechanism as a two-dimensional (2D) anode material. Furthermore, the Al₂C monolayer exhibits the ultrahigh specific capacity of lithium of 4059 mAh/g, yet with a low diffusion barrier of 0.039-0.17 eV and low open circuit voltage in the range of 0.002-0.34 V. These novel properties render the Al₂C monolayer a promising anode material for future lithium (ion) batteries. Our study also offers a design of promising 2D anode materials with a high specific capacity, fast lithium-ion diffusion, and safe lithium storage.

Synthesis and Study of Physical and Mechanical Properties of Urethane-Containing Elastomers Based on Epoxyurethane Oligomers with Controlled Crystallinity

The influence of the molecular weight of oligoamine, oligoether, and the type of diisocyanate on the physical and mechanical properties of elastomers with urethane hydroxyl hard segments was studied. For this purpose, oligoetherdiamines with molecular weights ~1008 and ~1400 g mol⁻¹ were synthesized by a three-stage method. Epoxyurethane oligomers were synthesized according to a two-step route with an oligodiisocyanate as an intermediate product. A series of 12 elastomers with controlled crystallinity were synthesized from these elastomers and amines. The deformation and strength properties of the elastomers were studied.

A Novel Material for High-Performance Li-O2 Battery Separator: Polyetherketone Nanofiber Membrane

The properties of separators significantly affect the efficiency, stability, and safety of the lithium-based batteries. Therefore, the improvement of the separator material is critical. Polyetherketone (PEK) has excellent general properties, such as mechanical strength, chemical stability, and thermal stability. Thus, it is expected to be an optimal separator material. However, its low solubility-induced poor processibility makes it difficult to be used for nanoscale product manufacturing. In this work, the soluble precursor polymer is prepared by introducing a "protecting" group into monomer, and fabricated into nanofiber membrane, which can be converted into polyetherketone nanofiber membrane by a simple acid treatment. The membrane prepared by this chemical-induced crystallization method exhibits superior chemical, thermal stability, and mechanical strength. Li-O₂ batteries with the fabricated membrane as separator have a high cycling stability (194 cycles at 200 mA g^-1 and 500 mAh g^-1 ). This work broadens the application field of PEK and provides a potential route for battery separators.