Long-term Cycling Stability Research Articles

A high-flash-point quasi-solid polymer electrolyte for stable nickel-rich lithium metal batteries

In the exploration of next-generation high-energy–density batteries, lithium metal is regarded as an ideal candidate for anode materials. However, lithium metal batteries (LMBs) face challenges in practical applications due to the risks associated with organic liquid electrolytes, among which their low flash points are one of the major safety concerns. The adoption of high flash point quasi-solid polymer electrolytes (QSPE) that is compatible with the lithium metal anode and high-voltage cathode is therefore a promising strategy for exploring high-performance and high-safety LMBs. Herein, we employed the in-situ polymerization of poly (epoxidized soya fatty acid Bu esters-isooctyl acrylate-ditrimethylolpropane tetraacrylate) (PEID) to gel the liquid electrolyte that formed a PEID-based QSPE (PEID-QSPE). The flash point of PEID-QSPE rises from 25 to 82 °C after gelation, contributing to enhanced safety of the battery at elevated temperatures, whereas the electrochemical window increases to 4.9 V. Moreover, the three-dimensional polymer framework of PEID-QSPE is validated to facilitate the uniform growth of the solid electrolyte interphase on the anode, thereby improving the cycling stability of the battery. By employing PEID-QSPE, the Li|LiNi0.9Co0.05Mn0.05O2 cell achieved long-term cycling stability (Coulombic efficiency, 99.8%; >200 cycles at 0.1 C) even with a high cathode loading (∼5 mg cm−2) and an ultrathin Li (∼50 μm). This electrolyte is expected to afford inspiring insights for the development of safe and long-term cyclability LMBs.

Modulating Electrochemical Energy Storage and Multi-Spectra Defense of MXenes by Interfacial Dual-Filler Engineering.

MXenes have attracted growing interest in electrochemical energy storage owing to their high electronic conductivity and editable surface chemistry. Besides, rendering MXenes with spectrum defense properties further broadens their versatile applications. However, the development of MXenes suffers from weak van der Waal interaction-driven self-restacking that leads to random alignment and inferior interface microenvironments. Herein, a nacre-inspired MXene film is tailored by dual-filling of 2-ureido-4[1H]-pyrimidinone (UPy)-modified polyvinyl alcohol (PVA-UPy) and carbon nanotubes (CNTs). The dual-nanofillers engineering endows the nanocomposite film with a highly ordered structure (a Herman's order value of 0.838), a high mechanical strength (139.5MPa), and continuous conductive pathways of both the ab plane and c-axis. As a proof-of-concept, the tailored nanocomposite film achieves a considerable capacitance of 508.2 F cm-3 and long-term cycling stability without performance degradation for 10000 cycles. It is efficient for spectra defense in radar and infrared bands, displaying a high electromagnetic shielding capacity (19186dB cm2 g-1) and a super-low infrared (IR) emissivity (0.16), with negligible performance decay after saving in the air for 1 year, responsible for the applications in specific and complex conditions. This interfacial dual-filler engineering concept showcases effective nanotechnology toward sustainable energy applications with a long lifetime and safety.

Synthesis and electrochemical performance of low cost nitrogen-doped carbon cryogel composites as supercapacitor electrodes

Developing cost-effective methods for synthesizing Nitrogen-doped carbon cryogels is crucial for advancing supercapacitor technology due to their enhanced electrochemical properties. Nitrogen-doped porous carbon cryogels are synthesized through the freeze-drying method by substituting resorcinol with phenol and using urea/melamine as nitrogen sources. The effect of nitrogen sources on the structure and electrochemical performance is investigated. In the case of carbon cryogel composites samples, using melamine as the nitrogen source (PMF) is more favorable than using urea (PUF), while both nitrogen-doped samples significantly outperform the undoped samples (PF). The PMF sample displays a specific surface area of 1119.00 m2 g−1, and a nitrogen content of 2.19 wt%. In the three-electrode system, the specific capacitance of the PMF sample reaches up to 247.9 F g−1 at a current density of 0.5 A g−1, and its rate performance is 85.52 %. By comparison, the PF sample exhibits specific capacitance and rate performance of 85.4 F g−1 and 33.44 % under the same parameters. The assembled symmetric supercapacitor in a buckle type system also demonstrates exceptional energy density (14.41 Wh kg−1), long-term cycle stability, and a favorable capacitance retention rate (72.2 %). These excellent electrochemical performances can be attributed to the synergistic effects of the hierarchical pore structures and heteroatoms doping.

Cellulose nanocrystals built multiscale hydrogel electrolyte for highly reversible all-flexible zinc ion batteries

Hydrogel electrolytes are promising for flexible and stable zinc ion batteries (ZIBs), but they lack fatigue resistance and still face challenges in terms of mechanical stability and durability. Herein, inspired by the hierarchical structure of biological networks, multiscale anti-fatigue hydrogel electrolytes with high toughness, high strength, and rapid recovery are constructed by introducing nanoscale cellulose nanocrystals (CNCs) as building blocks into dual-network cross-linking hydroxypropyl chitosan (HPCS) modified polyacrylamide (PAM) hydrogel (denoted as PHC-gel). As a result, the PHC-gel achieves a high fatigue threshold up to 356 J m−2 and with a superior strength and stretchability up to 180 kPa and 3178 %, respectively. In addition, the assembled Zn//Zn cell exhibits long-term cycling stability of 1800 h at 1 mA cm−2/1 mAh cm−2 with a high Coulombic efficiency of 99.4 %. More importantly, the Zn//PHC-gel//MnO2 flexible cell shows remarkable flexibility and capacity retention under different stretching and deformation conditions. This work demonstrates a promising gel chemistry that improves anti-fatigue properties and controls zinc behavior, offering great potential for high-performance flexible and wearable ZIBs and beyond.

Favored Amorphous LixSi Process with Restrained Volume Change Enabling Long Cycling Quasi-Solid-State SiOx anode.

Silicon-based anodes are becoming promising materials due to their high specific capacity. However, the intrinsically large volume change brought about by the alloying reaction results in the crushing of the active particles and destruction of the electrode structure, which severely limits its practical application. Various structured and modified silica-based anodes exhibit improved cycling stability and the demonstrated ability to mitigate their volume changes through interfacial and binder strategies. However, the issue of large volume changes in silicon-based anodes remains. Herein, we report a gel polymer electrolyte (GPE) prepared through an in situ thermal polymerization process that is suitable for SiOx anode materials and achieving long-term cycling stability. GPE-based cells essentially mitigate the volume change of SiOx anodes by guiding the unique lithiation/delithiation mechanism that tends to favor the formation and delithiation of amorphous-LixSi (a-LixSi) with smaller volume change, thereby mitigating electrode damage and cracking, and achieving the significant improvement in cycling performance. The prepared GPE-SiOx cells retained 693.80 mAh g-1 reversible capacity after 450 cycles at 500 mA g-1. In addition, the prelithiation process was incorporated to mitigate capacity fluctuations and improve the Initial Coulombic Efficiency (ICE), and a reversible capacity of 641.90 mAh g-1 was retained after 480 cycles.

Screen-Printable Iontronic Pressure Sensor with Thermal Expansion Microspheres for Pulse Monitoring.

Constructing microstructures to improve the sensitivity of flexible pressure sensors is an effective approach. However, the preparation of microstructures usually involves inverted molds or subtractive manufacturing methods, which are difficult in large-scale (e.g., in screen printing) preparation. To solve this problem, we introduced thermally expandable microspheres for screen printing to fabricate flexible sensors. Thermally expandable microspheres can be constructed into microstructures by simple heating after printing, which simplifies the microstructure fabrication step. In addition, the added microspheres can also be used as ionic liquid reservoir materials to further increase the capacitance change and improve the sensitivity. The prepared sensors exhibited superior performance, including ultrahigh sensitivity (Smax = 49999.5 kPa-1) and wide detection range (0-350 kPa). Even after 30,000 cycles at a high pressure of 300 kPa and a low pressure of 30 kPa, the sensor showed minimal signal degradation, demonstrating long-term cycling stability. In order to verify the practical potential of the sensors, we performed human radial artery beat detection experiments using these sensors. The variations in the intensity of the 3D radial artery pulse wave can be observed very clearly, which is important for human health monitoring. The above demonstrates that our strategy can provide an effective approach for the large-scale preparation of high-performance flexible pressure sensors.

Boosting Conversion of the Si-O Bond by Introducing Fe2+ in Carbon-Coated SiOx for Superior Lithium Storage.

SiOx-based anodes are of great promise for lithium-ion batteries due to their low working potential and high specific capacity. However, several issues involving large volume expansion during the lithiation process, low intrinsic conductivity, and unsatisfactory initial Coulombic efficiency (ICE) hinder their practical application. Here, an Fe-SiOx@C composite with significantly improved lithium-storage performance was successfully synthesized by combining Fe2+ modification with a carbon coating strategy. The results of both experiments and density functional theory calculations confirm that the Fe2+ modification not only effectively achieves uniform carbon coating but also weakens the bonding energy of the Si-O bond and boosts reversible lithiation/delithiation reactions, resulting in great improvement in the electrical conductivity, ICE, and reversible specific capacity of the as-obtained Fe-SiOx@C. Together with the coated carbon, the in situ-generated conductive Fe-based intermediates also ensure the electrical contact of active components, relieve the volume expansion, and maintain the structural integrity of the electrode during cycling. And the Fe-SiOx@C (x ≈ 1.5) electrode can deliver a high-rate capacity of 354 mA h g-1 at 2.0 A g-1 and long-term cycling stability (552.4 mA h g-1 at 0.5 A g-1 even after 500 cycles). The findings here provide a facile modification strategy to improve the electrochemical lithium-storage performance of SiOx-based anodes.

Electrocatalytic tungsten boride quantum dots anchored reduced graphene oxide as the desolvation promotor for efficient sulfur redox kinetics

Lithium-sulfur (Li-S) batteries boast a multitude of compelling attributes, chief among them being their exceptional energy density and relatively low raw material costs. However, the sluggish redox kinetics of sulfur stemming from the considerable desolvation energy barrier and the notorious shuttle effect of lithium polysulfides, pose significant challenges in the commercialization of Li-S batteries. In this work, ultra-fine WB quantum dots were in-situ and uniformly dispersed on reduced graphene oxide nanosheets (WB-rGO) by mild melting-salt method, in which the abundant oxygen-containing functional groups in graphene oxide effectively prevent the agglomeration of WB. Such ultra-fine WB quantum dot as well as dual-active sites stemming from W and electronics-deficient B, confer the WB-rGO composite with improved electrochemical active surface area for dissociating Li+-solvents molecules and catalyzing polysulfides transformations, thus improving cycling and rate performance of Li-S battery. Hence, the cells with WB-rGO@PP maintained a stable long-term cycling (650 mAh g−1 after 900 cycles at 1 C with an average decay rate of 0.038 % per cycle) and an impressive rate capability (740 mAh g−1 at 4 C). Even at a sulfur loading of 4.7 mg cm−2, the cell performed a high areal capacity of 3.6 mAh cm−2 after 200 cycles.

A Novel Gelatin Binder with Helical Crosslinked Network for High-Performance Si Anodes in Lithium-Ion Batteries.

Silicon(Si) is a promising anode material for lithium-ion batteries, but its large volume expansion during cycling poses a challenge for the binder design. In this study, a novel gelatin binder is designed and prepared with a helical crosslinked network structure. This gelatin binder is prepared by enzymatic crosslinking and immersion in Hofmeister salt solution, which induces the formation of network and helical secondary structures. The helical crosslinked network structure can be analogous to a spring group system to effectively dissipate the stress and strain caused by the Si expansion. The gelatin binder is further partially carbonized by low-temperature pyrolysis, which improves its conductivity and stability. The Sianode with the optimized gelatin binder exhibits high initial coulombic efficiency, excellent rate performance, and long-term cycling stability. This study provides an innovative approach for the preparation of high-performance Si anodes, namely by controlling the molecular configuration of the binder to significantly improve the cycle stability, which can also be applied to other high-capacity anode materials that suffer from large volume changes during cycling.

Ni/Ni4N nanoparticles anchored on 3D necklace-like carbon framework as free-standing bifunctional host for practical Li-S full cells

Inhibiting the shuttle effect, accelerating sulfur redox kinetics and controlling lithium homogeneous deposition are significant to achieve the flexible lithium-sulfur (Li-S) cells with high energy density and safety. In this study, we successfully synthesized a three-dimensional (3D) free-standing necklace-like fabric consisting of heterostructured Ni/Ni4N nanoparticles confined into hollow carbon cages implanted with N-doped carbon nanofibers (Ni/Ni4N@NCC). This unique 3D necklace-like framework and interface electronic structure of Ni/Ni4N@NCC could effectively addresses the challenges associated with both sulfur cathode and lithium anode in Li-S cells. Combine with experimental tests and DFT simulations, Ni/Ni4N@NCC not only strengthened chemical anchoring and accelerated lithium polysulfides conversion, but also induced Li uniform deposition and growth due to its excellent lithiophilicity and low Li diffusion energy barrier. For the anode, the lithium foil coating with Ni/Ni4N@NCC interlayer (denoted as Li-Ni/Ni4N@NCC anode) showed exceptional long-term cycling stability over 1000 h at the high current density of 5 mA cm−2 for high areal capacity of 5 mAh cm−2. The S-Ni/Ni4N@NCC||Li-Ni/Ni4N@NCC cell with sulfur loading (6.8mg cm−2) exhibited high areal capacities of 6.11 mAh cm−2. The synergetic effect of fascinating necklace-like structure and heterogeneous interface offer instruction for the practically viable design of high-performance flexible Li-S full cells.

Highly Tough Slide-Crosslinked Gel Polymer Electrolyte for Stable Lithium Metal Batteries.

Gel polymer electrolytes (GPEs) hold great promise for the practical application of lithium metal batteries. However, conventional GPEs hardly resists lithium dendrites growth and maintains long-term cycling stability of the battery due to its poor mechanical performance. Inspired by the slide-ring structure of polyrotaxanes (PRs), herein we developed a dynamic slide-crosslinked gel polymer electrolyte (SCGPE) with extraordinary stretchability of 970.93 % and mechanical strength of 1.15 MPa, which is helpful to buffer the volume change of electrodes and maintain mechanical integrity of the battery structure during cycling. Notably, the PRs structures can provide fast ion transport channels to obtain high ionic conductivity of 1.73×10-3 S cm-1 at 30 °C. Additionally, the strong polar groups in SCGPE restrict the free movement of anions to achieve high lithium-ion transference number of 0.71, which is favorable to enhance Li+ transport dynamics and induce uniform Li+ deposition. Benefiting from these features, the constructed Li|SCGPE-3|LFP cells exhibit ultra-long and stable cycle life over 1000 cycles and high-capacity retention (89.6 % after 1000 cycles). Even at a high rate of 16 C, the cells deliver a high capacity of 79.2 mAh g-1. The slide-crosslinking strategy in this work provides a new perspective on the design of advanced GPEs for LMBs.

Variant-Localized High-Concentration Electrolyte without Phase Separation for Low-Temperature Batteries.

Dual-ion batteries (DIBs) present great application potential in low-temperature energy storage scenarios due to their unique dual-ion working mechanism. However, at low temperatures, the insufficient electrochemical oxidation stability of electrolytes and depressed interfacial compatibility impair the DIB performance. Here, we design a variant-localized high-concentration solvation structure for universal low-temperature electrolytes (ν-LHCE) without the phase separation via introducing an extremely weak-solvating solvent with low energy levels. The unique solvation structure gives the ν-LHCE enhanced electrochemical oxidation stability. Meanwhile, the extremely weak-solvating solvent can competitively participate in the Li+-solvated coordination, which improves the Li+ transfer kinetics and boosts the formation of robust interphases. Thus, the ν-LHCE electrolyte not only has a good high-voltage stability of >5.5 V and proper Li+ transference number of 0.51 but also shows high ionic conductivities of 1 mS/cm at low temperatures. Consequently, the ν-LHCE electrolyte enables different types of batteries to achieve excellent long-term cycling stability and good rate capability at both room and low temperatures. Especially, the capacity retentions of the DIB are 77.7 % and 51.6 %, at -40 °C and -60 °C, respectively, indicating great potential for low-temperature energy storage applications, such as polar exploration, emergency communication equipment, and energy storage station in cold regions.

Se-dopant Modulated Selective Co-Insertion of H+ and Zn2+ in MnO2 for High-Capacity and Durable Aqueous Zn-Ion Batteries.

MnO2 is commonly used as the cathode material for aqueous zinc-ion batteries (AZIBs). The strong Coulombic interaction between Zn ions and the MnO2 lattice causes significant lattice distortion and, combined with the Jahn-Teller effect, results in Mn2+ dissolution and structural collapse. While proton intercalation can reduce lattice distortion, it changes the electrolyte pH, producing chemically inert byproducts. These issues greatly affect the reversibility of Zn2+ intercalation/extraction, leading to significant capacity degradation of MnO2. Herein, we propose a novel method to enhance the cycling stability of δ-MnO2 through selenium doping (Se-MnO2). Our work indicates that varying the selenium doping content can regulate the intercalation ratio of H+ in MnO2, thereby suppressing the formation of ZnMn2O4 by-products. Se doping mitigates the lattice strain of MnO2 during Zn2+ intercalation/deintercalation by reducing Mn-O octahedral distortion, modifying Mn-O bond length upon Zn2+ insertion, and alleviating Mn dissolution caused by the Jahn-Teller effect. The optimized Se-MnO2 (Se concentration of 0.8 at.%) deposited on carbon nanotube demonstrates a notable capacity of 386 mAh g-1 at 0.1 A g-1, with exceptional long-term cycle stability, retaining 102 mAh g-1 capacity after 5000 cycles at 3.0 A g-1.

Photo-rechargeable zinc-ion battery using highly ordered and vertically oriented C@VO2/ZnO microrod arrays

Development of photo-rechargeable batteries is a potential resolution for supplying off-grid solar power system in remote locations. Here, we present a photo-rechargeable zinc-ion battery (PRZIB) that can be directly recharged by the light without external photovoltaic cells and controllers. A highly ordered and vertically oriented ZnO microrod arrays (ZMRAs) were prepared using hydrothermal method in micron-scale patterned ZnO substrate defined by lithographic technology, which are used to incorporate with carbon encased vanadium oxide (C@VO2) nanocomposite to form a large specific surface area of three-dimensional network of C@VO2/ZnO heterojunction. PRZIB was assembled using C@VO2/ZMRAs structure as the photovoltaics as well as intercalation host for Zinc-ions, which demonstrates a photo-conversion efficiency of 3.3 % and gravimetric capacities of 286.0 mAh g−1 and 339.3 mAh g−1 at 500 mA g−1 in dark and light conditions. An excellent long-term cycling stability was achieved with a capacity retention of 88.79 % after 300 cycles at 1000 mA g−1 in dark condition. It is suggested that the distinctive morphologies and structure of C@VO2/ZMRAs provide effective strategies for enhancing photo-electrochemical redox reaction kinetics.

Nitrogen-based redox couple regulated anionic redox to long-term cycling stability of Li and Mn-rich layered oxide cathode for Li-ion batteries

Lithium and manganese-rich layered oxides (LMROs) have attracted extensive attention and are promising cathode materials for next-generation lithium ion batteries due to their high capacities and high energy densities. However, LMRO cathode suffers from severe capacity and voltage fading originating from irreversible surface oxygen evolution. Herein, we propose a facile redox couple strategy by introducing nitroxyl radicals species to regulate the surface anionic redox reaction of LMRO cathode. Differential electrochemical mass spectroscopy, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analyses demonstrate that during charge process, the peroxide ion O22− on the surface generated from the oxidation of lattice O2− could be reduced back to stable O2− by redox couple in time, thus avoiding oxygen evolution and structure degradation, as well as enhancing bulk oxygen redox activity. The enhanced LMRO electrode delivers a high capacity of 220.3 mAh g−1 at 1 C. An excellent cycling stability with a capacity retention of 94.4 % is achieved after 500 cycles, as well as a suppressed voltage decay with only 1.12 mV per cycle.

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.

In-situ growth of novel iron oxide/iron organic framework composites as efficient electroactive materials of battery supercapacitor hybrids

Iron oxide (Fe2O3) with a high theoretical capacitance, wide potential ranges and easy availability has attracted much attentions as the electrode material of battery supercapacitor hybrids (BSH). Metal–organic framework (MOF) is one of the promising potential energy storage materials due to its large surface area and controllable pore structures. In this work, novel iron oxide/iron organic framework composites (Fe2O3/FeMOF) are in-situ grown on the Ni foam as efficient energy storage electrodes of BSH. By tuning the solvothermal durations, the morphology changes from random sizes of sheets, regular grown vertical sheets, to flower-like structures. The d-spacing also increases for the Fe2O3/FeMOF synthesized using longer solvothermal durations. The optimal Fe2O3/FeMOF electrode synthesized using 9 h shows a high areal capacitance of 10.97 F/cm2 along with an areal capacity of 5.49 F/cm2 at the current density of 35 mA/cm2, owing to the most regular growth of sheets, the large d-spacing, and the smallest charge-transfer resistances. A BSH composed of the Fe2O3/FeMOF positive electrode and a graphene negative electrode shows a maximum energy density of 0.76 mWh/cm2 at 22.5 mW/cm2. The excellent long-term cycling stability with the capacitance retention of 85% and Coulombic efficiency of 98% are also achieved after 10,000 charge/discharge cycles.

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.

Lattice-confined localized alloying of Bi0.67TaS2 anode enabling ultrafast and stable sodium storage up to 150 C

Bismuth is considered to be a promising anode for sodium-ion batteries due to its low voltage plateau and high volumetric capacity. However, the large volume variation during alloying/dealloying leads to electrode pulverization and performance degradation, especially under high current densities. Herein we propose a lattice-confined localized alloying reaction mechanism to solve the above issues. By chemically embedding Bi atoms in a rigid layered ▪ host framework, the alloying reaction of Bi is spatially and kinetically confined within the ▪ interlayer, allowing for complete recovery of the Bi0.67TaS2 crystal structure after desodiation. The as-prepared Bi0.67TaS2 anode exhibits superior rate performance, achieving capacities of 256 mAh g ▪ at 1 C and 186 mAh g ▪ at 150 C, along with remarkable long-term cycling stability for maintaining 153 mAh g ▪ after 20000 cycles at 150 C. This work demonstrates that the localized alloying mechanism enabled by lattice confinement significantly contributes to both rate and cycling performance, which is expected to provide insights into electrode design for future fast-charging batteries.

Ultrathin Zn(002) textured zinc anodes for dendrite-free and hydrogen evolution-inhibited zinc batteries

For practical rechargeable aqueous zinc-ion batteries, the long-term cycling stability of the zinc anode remains significantly constrained by its low utilization efficiency and the persistent challenge of hydrogen evolution. This study demonstrates the fabrication of ultrathin zinc electrodes with a robust Zn (002) texture while ensuring an adequate supply of zinc metal for use as an anode material. This approach effectively suppresses the tendency of zinc atoms to undergo deposition transformation due to dislocation-induced phenomena. Compared to zinc foils with higher deposition amount, the ultrathin Zn anode exhibits enhanced resistance to dendrite growth and interfacial side reactions. Assembled symmetrical cells based on this ultra-thin Zn anode show a cycle life of 1750 h (1 mAcm−2, 0.5 mAhcm−2), maintaining stable cycling for over 100h even at a high depth of discharge (DOD) of 46.23%. Additionally, the full cell couple with V10O24 exhibits a high initial capacity of 429.6 mAh g−1 and a capacity retention of 75.8% after 1000 cycles.