3D Graphene Networks Encapsulated with Ultrathin SnS Nanosheets@Hollow Mesoporous Carbon Spheres Nanocomposite with Pseudocapacitance‐Enhanced Lithium and Sodium Storage Kinetics

The lithium and sodium storage performances of SnS anode often undergo rapid capacity decay and poor rate capability owing to its huge volume fluctuation and structural instability upon the repeated charge/discharge processes. Herein, a novel and versatile method is described for in situ synthesis of ultrathin SnS nanosheets inside and outside hollow mesoporous carbon spheres crosslinked reduced graphene oxide networks. Thus, 3D honeycomb‐like network architecture is formed. Systematic electrochemical studies manifest that this nanocomposite as anode material for lithium‐ion batteries delivers a high charge capacity of 1027 mAh g^?1 at 0.2 A g^?1 after 100 cycles. Meanwhile, the as‐developed nanocomposite still retains a charge capacity of 524 mAh g^?1 at 0.1 A g^?1 after 100 cycles for sodium‐ion batteries. In addition, the electrochemical kinetics analysis verifies the basic principles of enhanced rate capacity. The appealing electrochemical performance for both lithium‐ion batteries and sodium‐ion batteries can be mainly related to the porous 3D interconnected architecture, in which the nanoscale SnS nanosheets not only offer decreased ion diffusion pathways and fast Li⁺/Na⁺ transport kinetics, but also the 3D interconnected conductive networks constructed from the hollow mesoporous carbon spheres and reduced graphene oxide enhance the conductivity and ensure the structural integrity.     

Stabilization of Sn Anode through Structural Reconstruction of a Cu–Sn Intermetallic Coating Layer

The metallic tin (Sn) anode is a promising candidate for next-generation lithium-ion batteries (LIBs) due to its high theoretical capacity and electrical conductivity. However, Sn suffers from severe mechanical degradation caused by large volume changes during lithiation/delithiation, which leads to a rapid capacity decay for LIBs application. Herein, a Cu–Sn (e.g., Cu₃Sn) intermetallic coating layer (ICL) is rationally designed to stabilize Sn through a structural reconstruction mechanism. The low activity of the Cu–Sn ICL against lithiation/delithiation enables the gradual separation of the metallic Cu phase from the Cu–Sn ICL, which provides a regulatable and appropriate distribution of Cu to buffer volume change of Sn anode. Concurrently, the homogeneous distribution of the separated Sn together with Cu promotes uniform lithiation/delithiation, mitigating the internal stress. In addition, the residual rigid Cu–Sn intermetallic shows terrific mechanical integrity that resists the plastic deformation during the lithiation/delithiation. As a result, the Sn anode enhanced by the Cu–Sn ICL shows a significant improvement in cycling stability with a dramatically reduced capacity decay rate of 0.03% per cycle for 1000 cycles. The structural reconstruction mechanism in this work shines a light on new materials and structural design that can stabilize high-performance and high-volume-change electrodes for rechargeable batteries and beyond.     

中空海胆状结构的碳包覆Fe2O3用作锂离子电池的高性能负极材料

Fe2O3由于成本低廉,储量丰富和理论比容量高(1007 mA hg^-1)等特点,在锂离子电池负极材料的应用中极具发展前景.然而一些问题仍然存在,如:充放电过程中比容量的迅速衰减,不可逆的体积膨胀以及较短的循环寿命等.这些问题严重制约了Fe2O3在锂离子电池中的实际应用.为了突破这些局限,本文以金属-有机骨架(MOF...     

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 Li₄Ti₅O₁₂ 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.     

Superior performance for lithium storage from an integrated composite anode consisting of SiO-based active material and current collector

Silicon-based material is considered to be one of the most promising anodes for the next-generation lithium-ion batteries (LIBs) due to its rich sources, non-toxicity, low cost and high theoretical specific capacity. However, it cannot maintain a stable electrode structure during repeated charge/discharge cycles, and therefore long cycling life is difficult to be achieved. To address this problem, herein a simple and efficient method is developed for the fabrication of an integrated composite anode consisting of SiO-based active material and current collector, which exhibits a core–shell structure with nitrogen-doped carbon coating on SiO/P micro-particles. Without binder and conductive agent, the volume expansion of SiO active material in the integrated composite anode is suppressed to prevent its pulverization. At a current density of 500 mA·g⁻¹, this integrated composite anode exhibits a reversible specific capacity of 458 mA·h·g⁻¹ after 200 cycles. Furthermore, superior rate performance and cycling stability are also achieved. This work illustrates a potential method for the fabrication of integrated composite anodes with superior electrochemical properties for high-performance LIBs.     

Uniform Distribution of Alloying/Dealloying Stress for High Structural Stability of an Al Anode in High‐Areal‐Density Lithium‐Ion Batteries

Aluminum (Al) is one of the most attractive anode materials for lithium‐ion batteries (LIBs) due to its high theoretical specific capacity, excellent conductivity, abundance, and especially low cost. However, the large volume expansion, originating from the uneven alloying/dealloying reactions in the charge/discharge process, causes structural stress and electrode pulverization, which has long hindered its practical application, especially when assembled with a high‐areal‐density cathode. Here, an inactive (Cu) and active (Al) co‐deposition strategy is reported to homogeneously distribute the alloying sites and disperse the stress of volume expansion, which is beneficial to obtain the structural stability of the Al anode. Owing to the homogeneous reaction and uniform distribution of stress during the charge/discharge process, the assembled full battery (LiFePO₄ cathode with a high areal density of ≈7.4 mg cm^?2) with the Cu–Al@Al anode, achieves a high capacity retention of ≈88% over 200 cycles, suggesting the feasibility of the interfacial design to optimize the structural stability of alloying metal anodes for high‐performance LIBs.     

Improved electrochemical performance of silicon-carbon anodes by different conductive agents

Journal of Materials Science: Materials in Electronics - Silica/silicon/polyacrylonitrile (SiO2/Si/PAN) composites were prepared as active anode for lithium-ion batteries (LIBs) using a rational...     

Fe-Based Metal-Organic Framework and Its Derivatives for Reversible Lithium Storage

The use of a Fe-based metal organic framework(MOF), namely MIL-88B(Fe), as active material for lithium ion batteries(LIBs) is reported for the first time in the present work. Fe-based MOF demonstrated high capacity, excellent cycling stability and rate performance when used as anode. A highly reversible capacity of 680 mAhg~(-1) after 500 cycles at a current density of 200 m A g~(-1) was obtained. In addition, Fe_2O_3 and Fe_3O_4/C composites were obtained from Fe-based MOFs through thermal treatment. Both Fe_2O_3 and Fe_3O_4/C composites demonstrated high capacity and excellent cycling stability.     

MOF-derived carbon coating on self-supported ZnCo<Subscript>2</Subscript>O<Subscript>4</Subscript>–ZnO nanorod arrays as high-performance anode for lithium-ion batteries

The C–ZnCo₂O₄–ZnO nanorod arrays (NRAs), which consist of MOF-derived carbon coating on ZnCo₂O₄–ZnO NRAs, are rational designed and synthesized via a facile template-based solution route on Ti foil and used as high-performance anode for lithium-ion batteries (LIBs). The uniform coated MOF-derived carbon layers on the ZnCo₂O₄–ZnO nanorods surface can serve as a conductive substrate as well as buffer layer to restrain volume expansion during charge–discharge process. When tested as anodes for LIBs, the C–ZnCo₂O₄–ZnO NRAs show high reversible capacity of 1318 mA h g^?1 at 0.2 A g^?1 after 150 charge–discharge cycles. Furthermore, C–ZnCo₂O₄–ZnO NRAs also exhibit brilliant rate performance of 886.2, 812.8, 732.2 and 580.6 mA h g^?1 at 0.5, 1, 2 and 5 A g^?1, respectively. The outstanding lithium storage performance of C–ZnCo₂O₄–ZnO NRAs could be ascribed to the stimulated kinetics of ion diffusion and electron transport originated from the shortened lithium-ion diffusion pathway and improved electronic conductivity benefit from uniformly coating MOF-derived carbon.     

Phase Separation Derived Core/Shell Structured Cu11V6O26/V2O5 Microspheres: First Synthesis and Excellent Lithium‐Ion Anode Performance with Outstanding Capacity Self‐Restoration

Novel amorphous vanadium oxide coated copper vanadium oxide (Cu₁₁V₆O₂₆/V₂O₅) microspheres with 3D hierarchical architecture have been successfully prepared via a microwave‐assisted solution method and subsequent annealing induced phase separation process. Pure Cu₁₁V₆O₂₆ microspheres without V₂O₅ coating are also obtained by an H₂O₂ solution dissolving treatment. When evaluated as an anode material for lithium‐ion batteries (LIBs), the as‐synthesized hybrid exhibits large reversible capacity, excellent rate capability, and outstanding capacity self‐recovery. Under the condition of high current density of 1 A g^?1, the 3D hierarchical Cu₁₁V₆O₂₆/V₂O₅ hybrid maintains a reversible capacity of ≈1110 mA h g^?1. Combined electrochemical analysis and high‐resolution transmission electron microscopy observation during cycling reveals that the amorphous V₂O₅ coating plays an important role on enhancing the electrochemical performances and capacity self‐recovery, which provides an active amorphous protective layer and abundant grain interfaces for efficient inserting and extracting of Li‐ion. As a result, this new copper vanadium oxide hybrid is proposed as a promising anode material for LIBs.     

腈纶废丝/硬脂酸相变纤维的制备及性能研究

以硬脂酸(SA)为相变储能物质,腈纶废丝(PAN)为聚合物基体,采用湿法纺丝法制备了PAN/SA相变纤维。研究表明,相变纤维中PAN与SA大分子依靠分子间作用力结合在一起;SA在纤维基体中分布均匀,无相分离现象;PAN/SA相变纤维的相变焓达到48.84J/g,且DSC热循环显示纤维具有较好的热稳定性;PAN/SA相变纤维相对于PAN纤维具有良好的保温性;PAN/SA相变纤维在110℃热空气中迅速干燥的力学性能优于常温处理的力学性能。     

Nitrogen and Phosphorus Codoped Vertical Graphene/Carbon Cloth as a Binder‐Free Anode for Flexible Advanced Potassium Ion Full Batteries

With the fast development in flexible electronic technology, power supply devices with high performance, low‐cost, and flexibility are becoming more and more important. Potassium ion batteries (KIBs) have a brilliant prospect for applications benefiting from high voltage, lost cost, as well as similar electrochemistry to lithium ion batteries (LIBs). Although carbon materials have been studied as KIBs anodes, their rate capability and cycling stability are still unsatisfactory due to the large‐size potassium ions. Herein, a nitrogen (N) and phosphorus (P) dual‐doped vertical graphene (N, P‐VG) uniformly grown on carbon cloth (N, P‐VG@CC) is reported as a binder‐free anode for flexible KIBs. With the combined advantages of rich active sites, highly accessible surface, highly conductive network, larger interlayer spacing as well as robust structural stability, this binder‐free N, P‐VG@CC anode exhibits high capacity (344.3 mAh g^?1), excellent rate capability (2000 mA g^?1; 46.5% capacity retention), and prominent long‐term cycling stability (1000 cycles; 82% capacity retention), outperforming most of the recently reported carbonaceous anodes. Moreover, a potassium ion full cell is successfully assembled on the basis of potassium Prussian blue (KPB)//N, P‐VG@CC, exhibiting a large energy density of 232.5 Wh kg^?1 and outstanding cycle stability.     

MXenes for Rechargeable Batteries Beyond the Lithium‐Ion

Research on next‐generation battery technologies (beyond Li‐ion batteries, or LIBs) has been accelerating over the past few years. A key challenge for these emerging batteries has been the lack of suitable electrode materials, which severely limits their further developments. MXenes, a new class of 2D transition metal carbides, carbonitrides, and nitrides, are proposed as electrode materials for these emerging batteries due to several desirable attributes. These attributes include large and tunable interlayer spaces, excellent hydrophilicity, extraordinary conductivity, compositional diversity, and abundant surface chemistries, making MXenes promising not only as electrode materials but also as other components in the cells of emerging batteries. Herein, an overview and assessment of the utilization of MXenes in rechargeable batteries beyond LIBs, including alkali‐ion (e.g., Na⁺, K⁺) storage, multivalent‐ion (e.g., Mg²⁺, Zn²⁺, and Al³⁺) storage, and metal batteries are presented. In particular, the synthetic strategies and properties of MXenes that enable MXenes to play various roles as electrodes, metal anode protective layers, sulfur hosts, separator modification layers, and conductive additives in these emerging batteries are discussed. Moreover, a perspective on promising future research directions on MXenes and MXene‐based materials, ranging from material design and processing, fundamental understanding of the reaction mechanisms, to device performance optimization strategies is provided.     

Diatom Frustules Decorated with Co Nanoparticles for the Advanced Anode of Li-Ion Batteries

Silica is regarded as a promising anode material for lithium-ion batteries (LIBs) because of its high theoretical capacity. However, large volume variation and poor electrical conductivity are limiting factors for the development of SiO₂ anode materials. To solve this problem, combining SiO₂ with a conductive phase and designing hollow porous structures are effective ways. In this work, The Co(II)-EDTA chelate on the surface of diatom biosilica (DBS) frustules and obtained DBS@C-Co composites decorated with Co nanoparticles by calcination without a reducing atmosphere is first precipitated. The unique three-dimensional structure of diatom frustules provides enough space for the volume change of silica during lithiation/delithiation. Co nanoparticles effectively improve the electrical conductivity and electrochemical activity of silica. Through the synergistic effect of the hollow porous structure, carbon layer and Co nanoparticles, the DBS@C-Co-60 composite delivers a high reversible capacity of >620 mAh g⁻¹ at 100 mA g⁻¹ after 270 cycles. This study provides a new method for the synthesis of metal/silica composites and an opportunity for the development of natural resources as advanced active materials for LIBs.     

无黏结剂柔性Si/CNT/纤维素复合阳极及其电化学性能

硅/碳复合材料作为最具潜力的下一代阳极材料,受到广泛关注。为减少硅巨大膨胀所产生的应力,避免硅纳米颗粒的粉化,提高硅基锂离子电池的电化学性能,制备了一种多微孔结构的多壁碳纳米管(MWCNTs)纸,嵌入纳米硅制得Si/MWCNTs/纤维素复合柔性锂离子电池阳极。FESEM显示,纳米硅均匀地嵌入在MWCNTs构建的三维导电网络中,纳米硅和导电载体具有良好的接触,使得界面电阻大幅下降,同时纳米硅在电池充放电过程中具有足够的膨胀空间,保证了材料的结构稳定性和化学稳定性。电化学检测显示,其首次放电比容量达到2024 mAh/g,循环30次后比容量维持在850 mAh/g,展示出良好的循环稳定性和较高的比容量。同时,其制作工艺相比传统涂敷类阳极得以简化,可操作性高,易于实现产业化。     

高性能自支撑不锈钢网@MoS2锂离子电池负极材料

为了提高MoS₂作为Li离子电池负极材料整体的导电性和稳定性,将纳米化的MoS₂与其它导电性好的材料进行复合,通过水热法在导电基底不锈钢网(Stainless steel net, SS)上原位合成了一层MoS₂纳米花,制备了无粘结剂的自支撑结构的SS@MoS₂负极材料。纳米花状的MoS₂和导电性优异的SS提高了电子和Li离子的扩散速率,同时改善了电极的反应动力学。当作为Li离子电池负极材料时,SS@MoS₂电极表现出优异的储Li性能,特别是具有显著的大倍率充放电性能,即在1 000 mA/g的大电流密度下循环600次,比容量仍保持在862.1 mA·h/g。      

Ultrafine Sn nanocrystals in a hierarchically porous N-doped carbon for lithium ion batteries

We report a simple method of preparing a high performance,Sn-based anode material for lithium ion batteries (LIBs).Adding H2O2 to an aqueous solution containing Sn2+ and aniline results in simultaneous polymerization of aniline and oxidation of Sn2+ to SnO2,leading to a homogeneous composite of polyaniline and SnO2.Hydrogen thermal reduction of the above composite yields N-doped carbon with hierarchical porosity and homogeneously distributed,ultrafine Sn particles.The nanocomposite exhibits excellent performance as an anode material for lithium ion batteries,showing a high reversible specific capacity of 788 mAh·g-1 at a current density of 100 mA·g-1 after 300 cycles and very good stability up to 5,000 mA·g-1.The simple preparation method combined with the good electrochemical performance is highly promising to promote the application of Sn based anode materials.     

层状镍基锂离子电池正极材料的改性研究

详细阐述了国内外关于层状LiNiO2正极材料的改性研究进展,并对体相掺杂和表面包覆改性层状LiNiO2正极材料电化学性能提高的机理进行了讨论,最后对层状LiNiO2正极材料今后的发展方向进行了展望。     

Lithium Azides Induced SnS Quantum Dots for Ultra-Fast and Long-Term Sodium Storage

Tin sulfide (SnS) is an attractive anode for sodium ion batteries (NIBs) because of its high theoretical capacity, while it seriously suffers from the inherently poor conductivity and huge volume variation during the cycling process, leading to inferior lifespan. To intrinsically maximize the sodium storage of SnS, herein, lithium azides (LiN₃)-induced SnS quantum dots (QDs) are first reported using a simple electrospinning strategy, where SnS QDs are uniformly distributed in the carbon fibers. Taking the advantage of LiN₃, which can effectively prevent the growth of crystal nuclei during the thermal treatment, the well-dispersed SnS QDs performs superior Na⁺ transfer kinetics and pseudocapacitive when used as an anode material for NIBs. The 3D SnS quantum dots embedded uniformly in N-doped nanofibers (SnS QDs@NCF) electrodes display superior long cycling life-span (484.6 mAh g⁻¹ after 5800 cycles at 2 A g⁻¹ and 430.9 mAh g⁻¹ after 7880 cycles at 10 A g⁻¹), as well as excellent rate capability (422.3 mAh g⁻¹ at 20 A g⁻¹). This fabrication of transition metal sulfides QDs composites provide a feasible strategy to develop NIBs with long life-span and superior rate capability to pave its practical implementation.     

煤基球形多孔碳用于锂离子电池负极材料的性能研

因具有较短的锂离子扩散路径、大的比表面积等优势, 球形碳材料在锂离子电池负极材料中展露出良好的应用前景。研究以新疆库车产煤为原料, 采用电弧放电法及化学活化法制备出了具有多孔结构的煤基球形碳。通过X射线衍射(XRD)、扫描电镜(SEM)、拉曼光谱(Raman)、氮气吸脱附法和恒电流充放电等测试手段对材料结构、形貌和电化学性能进行了表征。结果表明, 在100 mA/g的电流密度下, 煤基球形多孔碳的首次放电比容量可达到1188.9 mAh/g, 远高于商业石墨负极372 mAh/g的理论比容量。此外, 该材料还表现出了良好的循环稳定性, 经历200圈循环后的放电比容量为844.9 mAh/g。煤基球形多孔碳优异的电化学性能得益于活化过程所产生的分级孔道结构能为锂离子提供更多储存空间, 从而提高了电极的容量及循环稳定性。