High Rate Capability Research Articles

A Unique Wide‐Spacing Fence‐Type Superstructure for Robust High‐Voltage O3‐Type Sodium Layered Cathode

AbstractEnhancing the energy density of layered oxide cathode materials is of great significance for realizing high‐performance sodium‐ion batteries and promoting their commercial application. Lattice oxygen redox at high voltage usually enables a high capacity and energy density. But the structural degradation, severe voltage decay, and the resultant poor cycling performance caused by irreversible oxygen release seriously restrict the practical application. Herein we introduce a novel fence‐type superstructure (2a×3a type supercell) into O3‐type layered cathode material Na0.9Li0.1Ni0.3Mn0.3Ti0.3O2 and achieve a stable cycling performance at a high voltage of 4.4 V. The fence‐type superstructure effectively inhibits the formation of the vacancy clusters resulting from out‐of‐plane Li migration and in‐plane transition metal migration at high voltage due to the wide d‐spacing, thereby significantly reducing the irreversible release of lattice oxygen and greatly stabilizing the crystal structure. The cathode exhibits a high energy density of 545 Wh kg−1, a high rate capability (112.8 mAh g−1 at 5 C) and a high cycling stability (85.8 %@200 cycles with a high initial capacity of 148.6 mAh g−1 at 1 C) accompanied by negligible voltage attenuation (98.5 %@200 cycles). This strategy provides a distinct spacing effect of superstructure to design stable high‐voltage layered cathode materials for Na‐ion batteries.

A Unique Wide-Spacing Fence-Type Superstructure for Robust High-Voltage O3-Type Sodium Layered Cathode.

Enhancing the energy density of layered oxide cathode materials is of great significance for realizing high-performance sodium-ion batteries and promoting their commercial application. Lattice oxygen redox at high voltage usually enables a high capacity and energy density. But the structural degradation, severe voltage decay, and the resultant poor cycling performance caused by irreversible oxygen release seriously restrict the practical application. Herein we introduce a novel fence-type superstructure (2a×3a type supercell) into O3-type layered cathode material Na0.9Li0.1Ni0.3Mn0.3Ti0.3O2 and achieve a stable cycling performance at a high voltage of 4.4 V. The fence-type superstructure effectively inhibits the formation of the vacancy clusters resulting from out-of-plane Li migration and in-plane transition metal migration at high voltage due to the wide d-spacing, thereby significantly reducing the irreversible release of lattice oxygen and greatly stabilizing the crystal structure. The cathode exhibits a high energy density of 545 Wh kg-1, a high rate capability (112.8 mAh g-1 at 5 C) and a high cycling stability (85.8 %@200 cycles with a high initial capacity of 148.6 mAh g-1 at 1 C) accompanied by negligible voltage attenuation (98.5 %@200 cycles). This strategy provides a distinct spacing effect of superstructure to design stable high-voltage layered cathode materials for Na-ion batteries.

Ultrafast Knock-Off Li+ Diffusion and Subtle Structural Evolution of Li5V3O8 Anode in Lithium-Ion Batteries.

Li5V3O8, a lithiation product derived from the LiV3O8 cathode, has emerged as a promising intercalation-type anode material, boasting a theoretical capacity of 256 mA h g-1. Through a comprehensive combination of experimental and theoretical approaches, we demonstrate its capability to intercalate a substantial amount of Li+ at extremely high rates. Experimental findings reveal that Li5V3O8 exhibits outstanding high-rate capability (with a specific capacity of 152 mA h g-1, 60% of the theoretical capacity at 40 C) and exceptional cyclability (with a capacity retention of 80% after 11,000 cycles at 20 C). The structural changes in Li5V3O8 during the lithiation/delithiation cycles are subtle and reversible. First-principles calculations highlight a knock-off mechanism in Li+ diffusion within Li5V3O8, with an estimated energy barrier ranging from 0.16 to 0.38 eV, considerably lower than that of a direct hopping mechanism (0.62-1.44 eV). These ultrafast ion diffusion properties are attributed to interlock interactions among interstitial tetrahedral Li+ and neighboring octahedral lattice Li+, facilitating long-distance and chain-like Li+ diffusion. This study not only introduces an influential vanadium-based anode material with practical implications for fast-charging lithium-ion batteries but also provides fundamental insights into solid state Li+ diffusion kinetics.

Dynamical Janus Interface Design for Reversible and Fast-Charging Zinc-Iodine Battery under Extreme Operating Conditions.

Aqueous zinc (Zn) iodine (I2) batteries have emerged as viable alternatives to conventional metal-ion batteries. However, undesirable Zn deposition and irreversible iodine conversion during cycling have impeded their progress. To overcome these concerns, we report a dynamical interface design by cation chemistry that improves the reversibility of Zn deposition and four-electron iodine conversion. Due to this design, we demonstrate an excellent Zn-plating/-stripping behavior in Zn||Cu asymmetric cells over 1000 cycles with an average Coulombic efficiency (CE) of 99.95%. Moreover, the Zn||I2 full cells achieve a high-rate capability (217.1 mA h g-1 at 40 A g-1; C rate of 189.5C) at room temperature and enable stable cycling with a CE of more than 99% at -50 °C at a current density of 0.05 A g-1. In situ spectroscopic investigations and simulations reveal that introducing tetraethylammonium cations as ion sieves can dynamically modulate the electrode-electrolyte interface environment, forming the unique water-deficient and chloride ion (Cl-)-rich interface. Such Janus interface accounts for the suppression of side reactions, the prevention of ICl decomposition, and the enrichment of reactants, enhancing the reversibility of Zn-stripping/-plating and four-electron iodine chemistry. This fundamental understanding of the intrinsic interplay between the electrode-electrolyte interface and cations offers a rational standpoint for tuning the reversibility of iodine conversion.

A gel polymer electrolyte obtained from cellulose acetate/polyvinylidene fluoride composite electrospun membrane for safe lithium metal batteries with high-rate capability

Li metal battery is a promising next-generation power storage devices, but faces the serious safety issues caused by the uncontrolled Li dendrite growth and leakage of the flammable organic electrolyte. Herein, a low-cost CA/PVDF (cellulose acetate/polyvinylidene fluoride) composite membrane is prepared via electrospinning technology for safe lithium metal batteries. This membrane (45 μm) exhibits the high porosity (76.9 %) and excellent thermally stability (>180 °C) preventing the short circuit during abuse. The CA/PVDF-based gel polymer electrolyte (GPE), fabricated with CA/PVDF electrospun membrane swelled by carbonate-based organic liquid electrolyte, delivers the ionic conductivity of 1.82 mS cm−1 and Li + transfer number of 0.506, which achieve uniform Li+ ion electrodeposition and inhibit the formation of lithium dendrites. As the results, the symmetrical cell Li/CA/PVDF-based GPE/Li exhibits the impressive reversible Li stripping/plating behavior over 300 h at 1 mA cm−2 with the capacity of 1 mA h cm−2. Furthermore, the assembled LiFePO4/GPE/Li battery exhibits the capacity of 101.2 mA h g−1 at 5C with the capacity retention of 94.6 % after 400 cycles, which exceeds that of traditional liquid electrolytes. This research provides a low-cost gel polymer electrolyte via the electrospinning technique for rechargeable lithium batteries with good electrochemical performance and high security.

Regulation of asymmetric bimetallic NiFe sites boost fast desolvation kinetics for long-cycling ammonium-ion storage

Aqueous ammonium ion battery (AAIB) is a new type of energy storage device with non-metallic ion (NH4+) as the carrier, possessing the apparent advantages of low cost, high safety, and long-term sustainability. However, the sluggish kinetics of the electrolyte-electrode interface often results in a slow NH4+ transport within the host structure, leading to poor cycling stability, especially in the type of cathode material with open frameworks represented by Fe-based Prussian blue analogues (PBAs). In this work, a NiFe-PBA (NiFe) cathode material with asymmetric bimetallic sites is purposely designed to regulate and improve the NH4+ desolvation kinetics at the electrolyte-electrode interface. Theoretical simulations first reveal that regulating the asymmetric bimetallic site effectively reduces the energy barrier of NH4+(H2O)4 desolvation at the electrolyte-electrode interface, and thus the NH4+(H2O)4 can be desolvated into NH4+ into host material. The electrochemical study results further show that the successful introduction of asymmetric bimetallic sites largely improves the diffusion kinetics and structural stability of FeFe-PBA (FeFe), realizing stable cycling performance (97 % retention after 700 cycles at 0.25 A g−1) and high-rate capability. Finally, in-situ characterizations in combination with theoretical calculations demonstrate that the insertion/extraction of NH4+ is attributed to the charge storage mechanism of reversible interactions in association with the coordination of N atoms in the NiFe-PBA.

Ultrahigh rate and cycling properties of Li2CuTi3O8 anode derived from HKUST-1 copper source for high-performance lithium-ion batteries

Rational design and preparation of titanium-based anode materials with superior fast charge and discharge are a key focuses of the lithium-ion batteries research. Herein, a novel and facile synthesis of uniformly carbon-coated Li2CuTi3O8 (LCuTO) nanoparticles with excellent high-rate lithium storage properties is presented using HKUST-1 with pore structure and active metal sites as a copper source. The well-designed LCuTO@HKUST with carbon bridges between the particles and the carbon layer on the outer surface offers high electronic conductivity for fast charge and discharge. The LCuTO@HKUST exhibits extraordinary lithium storage performance: high capacity (251.8 mAh/g after 1000 cycles at a current density of 1.0 A/g), a superior high-rate capability (160.3 mAh/g after 500 cycles at 3.0 A/g and 138.1 mAh/g after 500 cycles at 5.0 A/g), and excellent cycle reversibility and cycle stability under various current densities. In addition, the lower Li+ migration barrier in LCuTO@HKUST demonstrated by density functional theory (DFT) calculations is beneficial to the long-cycle stability and high-rate performance. The proposed preparation method and the strategy of using the MOF as a metal source for lithium-ion battery anode materials provide a new approach for advanced fast charge–discharge energy storage applications.

Improved rate capability and energy density of high-mass hybrid supercapacitor realized through long-term cycling stability testing and selective electrode design

To render supercapacitors (SCs) more practical, they must exhibit high cycling stability of at least ten thousand cycles with commercial-level mass loadings, which differentiates them from batteries. Metal-organic framework (MOF)-based electrode materials are promising for use in energy storage systems owing to their excellent electrochemical performance. In this study, we report the electroactivities of bimetallic MOFs (Co, Ni, and Co–Ni) using a single-step, facile, and cost-effective hydro/solvothermal method. To optimize their performances, we develop a general strategy for analyzing various binder-free MOFs. Additionally, the effects of the reaction time, reaction temperature, solvents, and elements (Ni, Co, and H2BDC) on the surface morphology and electrochemical performance are investigated. Based on an analysis of the electrochemical properties of all the synthesized electrode materials, the optimal electrode delivers an ultrahigh areal capacity of 2621 µAh cm−2 (297.1 mAh g−1) at 7 mA cm−2, with a high-rate capability of 82.5 % even at 40 mA cm−2. The optimized Co–Ni MOF electrode is employed as a positive electrode to fabricate an aqueous hybrid SC (HSC) with an activated carbon-coated nickel foam electrode as a negative electrode. The as-fabricated HSC exhibits excellent electrochemical properties with exceptional cycling stability (120k cycles) and improved rate capability (60 %). Additionally, we identify factors that contribute to improved redox reactions in the Co–Ni MOF-based HSC, such as the role of Co–Ni MOFs in the redox reaction and the influences of other structural parameters on charge storage and transfer processes. Our aim is to further understand the underlying mechanisms of the improved redox reactions and thus obtain new insights into the design and optimization of Co–Ni MOF-based HSCs. Finally, the energy storage properties of the HSC are validated by using it to power different electronic devices. The promising outcomes obtained in this work can serve as a basis for the future practical implementation of high-energy-density HSCs with high mass loadings and charging rates. SynopsisTo render the practicability of hybrid supercapacitor (HSC) with enhanced energy storage properties, we investigate the electroactivities of bimetallic metal-organic frameworks (MOFs) (Co, Ni, and Co–Ni) using a single-step, facile, and cost-effective hydro/solvothermal method. To optimize their performances, a general strategy is developed for analyzing various binder-free MOFs. Additionally, the effects of the reaction time, reaction temperature, solvents, and elements (Ni, Co, and H2BDC) on the surface morphology and electrochemical performance are studied. In addition, we validate the energy storage properties of the HSC by using it to power different electronic devices. The promising outcomes obtained in this study can serve as a basis for the future practical implementation of high-energy-density HSCs with high mass loadings and charging rates.

Lithiophilic Dibenzamide Linkages to Impart Lithium Storage Capacity in Porous Polybenzamides.

Polymer-based organic cathode materials have shown immense promise for lithium storage, owing to their structural diversity and functional group tunability. However, designing appropriate high-performance cathode materials with a high-rate capability and long cycle life remains a significant challenge. It is quintessential to design polymer-based electrodes with lithiophilic linkages. Herein, we design a bifurcated dibenzamide (DBA) linkage having lithiophilic functionalities. 1H NMR has been used as an experimental tool to understand the lithiophilic nature of the DBAs. Considering the strong Li+ affinity of DBAs, a series of polybenzamides have been designed as lithium storage systems. The design of porous polybenzamides consists of amides as only redox-active functionalities, and the rest are inactive phenyl units. Porous polybenzamides, when tested as cathodes against a Li-metal anode, displayed high capacity and rate performance, demonstrating their redox activity. The most efficient polybenzamide (TAm-TA) delivered a specific capacity of 248 mA h g-1 at 1C. TAm-TA retained 63% of its specific capacity at a very high rate of 10C (157 mA h g-1). Notably, polybenzamides displayed a capacity enhancement during long cycling, tending to achieve their theoretical capacity. Long cycling stability tests over 3000 cycles at a rate of 1.3C and over 6000 cycles at elevated rates (5C to 40C) demonstrate the electrochemical robustness of dibenzamide linkages. Finally, two full-cell experiments using TAm-TA as both cathode and anode were conducted, which delivered high capacity, demonstrating that TAm-TA is a promising candidate for Li+-ion batteries (LIBs). Furthermore, the ex situ Fourier transform infrared (FT-IR), X-ray photoemission spectroscopy (XPS), and density functional theory (DFT) studies revealed the stepwise lithiation/delithiation mechanism for polybenzamides.

Ultrathin composite Al2O3/LiAlO2 coating on truncated octahedral shape Co-free LiNi0.5Mn1.5O4 for enable high performance Li-ion battery

The Co-free cathode material of spinel LiNi0.5Mn1.5O4 (LNMO) has gained much interest for next-generation batteries owing to its 3D ionic channel for fast Li+ ion diffusion and high voltage operation. In this work, ultrathin composite Al2O3/LiAlO2 is adopted to modify truncated octahedral shape Fd3¯m spinel LNMO. It is found that 1 wt% Al coating modification exhibits the most excellent cycling performances, providing great capacity retention of 84.99 % for 350 cycles between 3.5 and 4.8 V at 1C. The homogeneous composite Al2O3/LiAlO2 coating on the truncated octahedral shape particle can deliver high rate capability of 40 mAh/g at 20C, charging and discharging. In addition, the ultrathin composite Al2O3/LiAlO2 coating can provide a stable interface, producing a high capacity retention of 94.82 % after 100 cycles at 45 °C. High performances of truncated octahedral shape Fd3¯m LNMO by composite Al2O3/LiAlO2 coating can enhance the safety and increase the potential applications of these cathode materials in the next-generation batteries.

Across Interfacial Li+ Conduction Accelerated by a Single-Ion Conducting Polymer in Ceramic-Rich Composite Electrolytes for Solid-State Batteries.

Composite electrolytes have been accepted as the most promising species for solid-state batteries, exhibiting the synergistic advantages of solid polymer electrolytes (SPEs) and solid ceramic electrolytes (SCEs). Unfortunately, the interrupted Li+ conduction across the SPE and SCE interface hinders the ionic conductivity improvement of composite electrolytes. In our study on a ceramic-rich composite electrolyte (CRCE) membrane composed of borate polyanion-based lithiated poly(vinyl formal) (LiPVFM) and Li1.3Al0.3Ti1.7(PO4)3 (LATP) particles, it is found that the strong interaction between the polyanions in LiPVFM and LATP particles results in a uniform distribution of ceramic particles at a high proportion of 50 wt % and good robustness of the electrolyte membrane with a Young's modulus of 9.20 GPa. More importantly, ab initio molecular dynamics simulation and experimental results demonstrate that Li+ conduction across the SPE and SCE interface is induced by the polyanion-based polymer due to its high lithium-ion transference number and similar Li+ diffusion coefficient with the SCE. Therefore, the unblocked Li+ conduction among ceramic particles dominates in the CRCE membrane with a high ionic conductivity of 6.60 × 10-4 S cm-1 at 25 °C, a lithium-ion transference number of 0.84, and a wide electrochemical stable window of 5.0 V (vs Li/Li+). Consequently, the high nickel ternary cathode LiNi0.8Mn0.1Co0.1O2-based batteries with CRCE deliver a high-rate capability of 135.08 mAh g-1 at 1.0 C and a prolonged cycle life of 100 cycles at 0.2 C between 3.0 and 4.3 V. The polyanion-induced Li+ conduction across the interface sheds new light on solving composite electrolyte problems for solid-state batteries.

Regulation of Interfacial Chemistry Enabling High-Power Dual-Ion Batteries at Low Temperatures.

Interfacial chemistry plays a crucial role in determining the electrochemical properties of low-temperature rechargeable batteries. Although existing interface engineering has significantly improved the capacity of rechargeable batteries operating at low temperatures, challenges such as sharp voltage drops and poor high-rate discharge capabilities continue to limit their applications in extreme environments. In this study, an energy-level-adaptive design strategy for electrolytes to regulate interfacial chemistry in low-temperature Li||graphite dual-ion batteries (DIBs) is proposed. This strategy enables the construction of robust interphases with superior ion-transfer kinetics. On the graphite cathode, the design endues the cathode interface with solvent/anion-coupled interfacial chemistry, which yields an nitrogen/phosphor/sulfur/fluorin (N/P/S/F)-containing organic-rich interphase to boost anion-transfer kinetics and maintains excellent interfacial stability. On the Li metal anode, the anion-derived interfacial chemistry promotes the formation of an inorganic-dominant LiF-rich interphase, which effectively suppresses Li dendrite growth and improves the Li plating/stripping kinetics at low temperatures. Consequently, the DIBs can operate within a wide temperature range, spanning from -40 to 45°C. At -40°C, the DIB exhibits exceptional performance, delivering 97.4% of its room-temperature capacity at 1C and displaying an extraordinarily high-rate discharge capability with 62.3% capacity retention at 10C. This study demonstrates a feasible strategy for the development of high-power and low-temperature rechargeable batteries.

A highly stable insertion type V1-xTixP solid solution as an anode material for high-rate lithium-ion batteries

As electric vehicles (EVs) grow in popularity, the demand for lithium-ion batteries (LIBs) simultaneously grows, and the fast-charging capability is becoming increasingly important. However, it is generally believed that graphite anode still suffers from a poor rate capability for fast-charging applications, and other insertion-type oxide anodes with a high rate capability exhibit too high Li+-ion insertion/extraction potential, which cannot meet a requirement for high energy density anodes. In this work, the hexagonal structure of V1-xTixP (x = 0.0, 0.25, and 1.0) phases were introduced as insertion-type anode materials for LIBs with a low reaction potential of Li+-ion insertion/extraction. The crystal structure and the corresponding electrochemical reaction mechanism of insertion-type anodes of TiP, VP, and MoP were compared. A facile strategy forming a substitutional solid solution is suggested to improve the electrochemical properties of anode materials by combining the end members among insertion-type VP, TiP, and MoP as forming V1-xTixP and V1-xMoxP compounds. V1-xTixP (x = 0.25) electrode, substituting V atoms with Ti atoms in VP structure, shows excellent long-term cycle stability at 1 A/g with a cycle retention of 87.7 % during 2500 cycles, delivering a two times higher capacity of 211.1 mAh g−1 compared to that of the commercial graphite electrode.

Barrel effect of high-rate capability determined by anode for LiNi0.5Co0.2Mn0.3O2/graphite lithium-ion battery

To date, charging time remains a critical issue that impedes the widespread application of lithium-ion batteries (LIBs). A comprehensive understanding of the attenuation mechanism of LIBs at high (dis)charging rates is essential for clarifying application strategies for extreme operating conditions and environments, thereby enhancing battery control, and guiding the design of advanced batteries with superior rate capability. In line with this focus, particular commercial NCM/graphite batteries were explored under various high-rate (dis)charging procedures, alongside the investigation of the impact of constant voltage steps on battery performance. This exploration revealed that capacity degradation occurs in three stages, and the rate of capacity decay is directly proportional to the (dis)charging rate. Furthermore, the in-situ temperature and stress of the battery during cycling, primarily caused by side reactions, were monitored to confirm the thermal effects and stress variations under high-rate conditions. By characterizing the morphology and composition of the electrode surface after post-mortem analysis, the “barrel effect” of high-rate capability determined by the anode electrode for LIBs is proposed. This research aims to establish optimal guidelines for designing batteries with excellent high-rate properties and to provide solutions for improving the safety and reliability of batteries applied in high-rate conditions.

Oriented Structures for High Safety, Rate Capability, and Energy Density Lithium Metal Batteries.

Lithium metal batteries (LMBs) have emerged in recent years as highly promising candidates for high-density energy storage systems. Despite their immense potential, mutual constraints arise when optimizing energy density, rate capability, and operational safety, which greatly hinder the commercialization of LMBs. The utilization of oriented structures in LMBs appears as a promising strategy to address three key performance barriers: 1) low efficiency of active material utilization at high surface loading, 2) easy formation of Li dendrites and damage to interfaces under high-rate cycling, and 3) low ionic conductivity of solid-state electrolytes in high safety LMBs. This review aims to holistically introduce the concept of oriented structures, provide criteria for quantifying the degree of orientation, and elucidate their systematic effects on the properties of materials and devices. Furthermore, a detailed categorization of oriented structures is proposed to offer more precise guidance for the design of LMBs. This review also provides a comprehensive summary of preparation techniques for oriented structures and delves into the mechanisms by which these can enhance the energy density, rate capability, and safety of LMBs. Finally, potential applications of oriented structures in LMBs and the crucial challenges that need to be addressed in this field are explored.

Dynamic magnesiothermic reduction of various silica to porous silicon structures for lithium battery anodes

A dynamic magnesiothermic reduction (DMR) of various silica having different size and porosity is conducted to study the effects of silica properties on the ⅰ) DMR reaction kinetics, ⅱ) properties of resulting porous silicon (pSi) microparticles, and ⅲ) performances of pSi/C composites as anodes in lithium batteries. A DMR kinetic study using the Ginstling–Brounstein diffusion model shows that the smaller the silica particle size, the higher the reduction rate and the lower the apparent activation energy. Irrespective of silica properties, all the resulting pSi particles have mesoporous structures. The pSi particles comprise interconnected small primary silicon nanoparticles (approximately 30–40 nm in diameter) to render similar particle morphologies to those of the parent silica. Owing to these appealing features of pSi particles, pSi/C composites exhibit excellent cycling performance for over 200 cycles and high rate capabilities, whereas SiMP/C (prepared with a non-porous silicon microparticles) loses most of its capacity in early cycles owing to high resistance build-up during cycling. Overall, the DMR of silica precursors of several micrometers or less in size (preferably porous precursors) are desirable for the production of high-purity pSi microparticles for use in high-capacity and stable anodes for advanced lithium batteries.

A Nanostructured Phenazine‐based Conjugated Microporous Polymer Hybrid Anode Boosts Power and Practicability of Organic‐Manganese Hydronium‐ion Batteries

Organic‐manganese hydronium‐ion batteries are gaining attention for their safety, sustainability, and high rate capabilities. However, their electrochemical performance faces challenges due to organic active‐materials' inferior properties, including low conductivity and solubility, and limited content (<60 wt%) and loading (<2 mg/cm2) in the anode. To address this, we developed a high‐performance battery using a phenazine‐based conjugated microporous polymer hybrid anode (IEP‐27‐SR), utilizing hydronium‐ion coordination/un‐coordination chemistry. The IEP‐27‐SR features enhanced structural characteristics, such as high BET specific surface area, mixed micro‐/mesoporosity, nanostructurization, and hybridization, enabling rapid hydronium‐ion mobility. The resulting IEP‐27‐SR//MnO2@GF full‐cell demonstrates high capacity (101 mAh/g at 2C), excellent rate performance (41 mAh/g at 100C), ultrafast‐charging capability (80% charged in 18 seconds), and impressive cyclability with 83% capacity retention over 20400 cycles at 30C with a regular polymer mass loading of 2 mg/cm2, despite its high content (80 wt%) in the anode. Moreover, it shows operability at low temperatures (63 mAh/g at ‐40 ºC). Most importantly, full‐cell with a high‐mass‐loading polymer anode (30 mg/cm2) achieves practically relevant areal capacity (3.4 mAh/cm2 at 4 mA/cm2) and sustains 2 mAh/cm2 under an extremely high areal current (50 mA/cm2). This breakthrough highlights the progress of organic hydronium‐ion batteries, representing progress toward practical battery solutions

Vacancies-Induced Delocalized States Cobalt Phosphide for Binder-Free Anode Toward Stable and High-Rate Sodium-Ion Batteries.

Metal phosphides with easy synthesis, controllable morphology, and high capacity are considered as potential anodes for sodium-ion batteries (SIBs). However, the inherent shortcomings of metal phosphating materials, such as conductivity, kinetics, volume strain, etc are not satisfactory, which hinders their large-scale application. Here, a CoP@carbon nanofibers-composite containing rich Co─N─C heterointerface and phosphorus vacancies grown on carbon cloth (CoP1-x@MEC) is synthesized as SIB anode to accomplish extraordinary capacity and ultra-long cycle life. The hybrid composite nanoreactor effectively impregnates defective CoP as active reaction center while offering Co─N─C layer to buffer the volume expansion during charge-discharge process. These vast active interfaces, favored electrolyte infiltration, and a well-structured ion-electron transport network synergistically improve Na+ storage and electrode kinetics. By virtue of these superiorities, CoP1-x@MEC binder-free anode delivers superb SIBs performance including a high areal capacity (2.47 mAh cm-2@0.2mA cm-2), high rate capability (0.443 mAh cm-2@6mA cm-2), and long cycling stability (300 cycles without decay), thus holding great promise for inexpensive binder-free anode-based SIBs for practical applications.

Constructing interfacial chemical interaction of dual-carbon protected cobalt diselenide anode for sodium storage

Transition metal selenides are attracting enormous attention due to their high theoretical capacity and appropriate working potential for sodium storage, while their intrinsic low electronic conductivity and large volume expansion during the cycling processes inevitably result in inadequate rate performance and inferior cycling stability. Herein, cobalt diselenide-based hollow sugarloaf-like self-supporting fiber membranes with strong interfacial chemical (Co-C) bonds have been reported for sodium-ion batteries (SIBs) via the dual-carbon protection strategy. Based on X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) combined with density functional theory (DFT), A built-in electric field is generated at the interface between CoSe2/C and CNFs, which provides a strong driving force for electron transfer and ion migration, making the optimal CoSe2/C−0.3@CNFs anode over 67.8 % of capacity retention from 0.1 to 5 A/g and maintained about 269.5 mAh/g of discharge capacity at 5 A/g. The strong interfacial Co-C bonds in CoSe2/C@CNFs enhance the interfacial affinity between CoSe2/C and CNFs, making it easier for CoSe2/C to trap sodium ions and effectively resist the volume expansion during cycling, thus showing excellent cyclic stability with a reversible capacity of 247.6 mA h g−1 at 1.0 A/g after 2600 cycles. The sodium storage mechanism of CoSe2/C−0.3@CNFs electrode in SIBs is systematically analyzed via in-situ XRD and in-situ Raman spectra. This study provides an effective approach to constructing heterostructured composites with strong chemical bonds and built-in electric field characteristics for high-rate capability and long-cycle stability SIBs. Moreover, the sodium ion diffusion kinetics in the CoSe2/C−0.3@CNFs anode is also revealed.

Inducing and Understanding Pseudocapacitive Behavior in an Electrophoretically Deposited Lithium Iron Phosphate Li-Metal Battery as an Electrochemical Test Platform.

Our study has effectively employed electrophoretic deposition (EPD) using AC voltage to develop a lithium iron phosphate (LFP) Li-ion battery featuring pseudocapacitive properties and improved high C-rate performance. This method has significantly improved the battery's specific capacity, achieving an impressive 100 mAhg-1 at a 5 C discharge rate, which showcases its superior high-rate capability. Additionally, the battery displayed excellent reversibility during its performance cycles. These results confirm the EPD method's efficacy in improving LFP electrode performance, yielding notable improvements in cycling stability and high-rate capability. The enhanced capacity and high-rate performance of the electrophoretic-deposited LFP electrodes are largely due to the fast kinetics facilitated by pseudocapacitive behavior-induced charge storage and a high Li-ion diffusion constant measured in our EPD-deposited LFP electrodes. This underscores the practicality of our approach and the development of a fundamental test platform to investigate the pseudocapacitive charge storage mechanism in electrodes with typical battery-like behavior.