锡钴合金电沉积层的结构与锂离子嵌脱行为

应用电沉积方法制备Sn-Co合金镀层.X-射线衍射和扫描电子显微镜分析表明,该Sn-Co合金镀层为六方固溶体结构,含Co量为20%的Sn-Co合金,其沉积层呈现(110)择优取向.表面微孔随沉积层Co含量的增加而增多.以Sn-Co合金镀层作锂离子电极材料,电化学性能测试表明,其首次充电曲线表现出锡钴合金、锡及锡氧化物与锂合金化的多个反应综合特征,随后的充电曲线趋于稳定,呈现L i-Sn-Co合金化反应特征;具有择优取向和多孔结构的Sn-Co合金电极材料的充放电性能较好,首次库仑效率为63.9%,经过20次充放电循环后,其充电容量为461mAg/h,库仑效率为99%.     

Hexagonal‐Shaped Tin Glycolate Particles: A Preliminary Study of Their Suitability as Li‐Ion Insertion Electrodes

Tin glycolate particles were prepared by a simple, one‐step, polyol‐mediated synthesis in air in which tin oxalate precursor was added to ethylene glycol and heated at reflux. Hexagonal‐shaped, micron‐sized tin glycolate particles were formed when the solution had cooled. A series of tin oxides was produced by calcination of the synthesized tin glycolate at 600–800 °C. It was revealed that the micron‐sized, hexagonal‐shaped tin glycolate now consisted of nanosized tin‐based particles (80–120 nm), encapsulated within a tin glycolate shell. XRD, TGA, and FT‐IR measurements were conducted to account for the three‐dimensional growth of the tin glycolate particles. When applied as an anode material for Li‐ion batteries, the synthesized tin glycolate particles showed good electrochemical reactivity in Li‐ion insertion/deinsertion, retaining a specific capacity of 416 mAh g^?1 beyond 50 cycles. This performance was significantly better than those of all the other tin oxides nanoparticles (<160 mAh g^?1) obtained after heat treatment in air. We strongly believe that the buffering of the volume expansion by the glycolate upon Li–Sn alloying is the main factor for the improved cycling of the electrode.     

锂离子电池碳包覆锡负极性能研究

应用水热法分解葡萄糖制作锂离子电池碳包覆锡负极. 充放电测试表明,添加5%（by mass）乙炔黑导电剂的该电极初始放电比容量达967 mAh.g^-1,经50周循环其放电比容量仍保持362 mAh.g^-1,远高于锡电极的比容量（50周循环166 mAh.g^-1）. 碳包覆可防止锡粉团聚,降低锡的不可逆容量损失. 而添加乙炔黑可降低碳包覆电极与电解液间的交流阻抗,改善电极内部锂离子及电子的传导通道,从而也提高了该电极的初始放电比容量.     

纳米钴基氧化物锂离子电池负极材料的研究

采用流变相法合成Co3 O4 ,CoB1.3 6 O2 .8,CoB0 .5Al0 .1O1.5样品 ,并研究其作为锂离子电池负极材料的电化学性能 .当电池在 0 .0 1～ 3.0 0V的电压范围之间循环时 ,Li/Co3 O4 电池表现出最好的充放电性能 :循环 30周后 ,可逆比容量仍能保持为初始比容量 (931mAh/g)的 95 % .掺杂了B ,Al材料 ,其可逆比容量与未掺杂的相比明显降低 ,而且第 1周可逆容量随掺杂的B、Al量的增加而减少 .通过异位XRD方法研究了不同充放电态Co3 O4 电极材料结构的变化 .结果表明 ,Co3 O4 电极在充放电过程中与Li的反应机理不同于传统的过渡金属与Li的反应机理 ,即非Li+ 的嵌入 /脱出或合金的形成 ,而是Co3 O4 的可逆还原氧化以及Li2 O的可逆形成与分解机理     

锂离子电池锂锰氧化物高压嵌锂材料的结构和电化学性能研究

利 用 Ｘ Ｒ Ｄ、 Ｉ Ｃ Ｐ、 Ｔ Ｇ Ａ 、 Ｄ Ｔ Ａ 及 恒 流 充 放 电 等 方 法 研 究 分 析 了 一 种 特 殊 天 然 结 构 Ｍｎ Ｏ２（ Ｎ Ｍ Ｄ） 材料的结 构、组成 以及电 化学嵌锂 特性． Ｘ Ｒ Ｄ 分析 表明,该样 品材料 是由钠水 锰矿以及水羟 锰矿复 合结构组 成的 Ｍｎ Ｏ２ 纳米 纤 维． 充放 电 循环 结果 显 示,其 前 期循 环容 量 可高 达 １５０ｍ Ａｈ／ ｇ 左 右,但性 能尚不够 稳定． 本文采 用一种 水热法高 压嵌锂处 理,可将 Ｎ Ｍ Ｄ 样品 转变为 具有３ ×３ 大隧道结 构的钡 镁锰矿（ Ｔｏｄｏｒｏｋｉｔｅ） 型锂 锰氧 化 物,既 增 强了 Ｌｉ ＋ 嵌 入 隧道 或 层间 结 构 的循环稳定 性． 并 显著提 高锂锰氧 化物电 极材料性 能的 稳定 性,以 充放 电电 流密 度 为０ ．８ ｍ Ａ／ｃ ｍ ２ ,经过１８０ 次 循环后 其比容量 仍具有 １１０ ｍ Ａｈ／ ｇ ． 该类 大隧道结 构锂锰 氧化物可 作为一 种３ Ｖ 的锂离子电极 材料．     

Microwave assisted hydrothermal synthesis of tin niobates nanosheets with high cycle stability as lithium-ion battery anodes

SnNb₂O₆ and Sn₂Nb₂O₇ nanosheets were synthetized via microwave assisted hydrothermal method, and innovatively employed as anode materials for lithium-ion battery. Compared with Sn₂Nb₂O₇ and the previously reported pure Sn-based anode materials, the SnNb₂O₆ electrode exhibited outstanding cycling performance.     

Titania nanotube supported tin anodes for lithium intercalation

A new type of nanostructured titania nanotube supported tin anode was prepared for lithium ion batteries. The as-prepared titania nanotubes are in the anatase phase with diameters of about 12 nm. Tin nanoparticles are dramatically decorated on the titania nanotubes and have a particle size of about 10 nm. This new structure promises good retention of reversible capacity on cycling for lithium intercalation. By charge/discharge measurements, the reversible capacity of the titania nanotubes supported tin anode for lithiation and de-lithiation was found to be 312 mA h/g (cycled between 0.05 and 2.0 V) and 203 mA h/g (cycled between 0.05 and 1.3 V) after 50 cycles with around 100% columbic efficiency.     

The one-step preparation and electrochemical characteristics of tin dioxide nanocrystalline materials

Tin dioxide nanocrystallines were prepared by one-step synthesis method – using amphiphilic P123 as a template. The crystalline nanomaterials present the uniform nano-size 15 nm and somewhat ordered porous meso-frameworks with average pores sizes of 3.5 and 9.5 nm. Meanwhile, the nanomaterials as the anode materials in lithium ion battery deliver high reversible capacity 792 mAh g⁻¹ in the first cycle, which is equal to the theoretical capacity. No aggregation of nano-tin particles was observed and the cracking of structure by the large volume change is efficiently limited owing to the porous mesostructured nanomaterials in the charge/discharge processes. The improved electrochemical properties are attributed to the particle size and structure of materials.     

SnO2 negative electrode for lithium ion cell: in situ Mössbauer investigation of chemical changes upon discharge

In situ ¹¹⁹Sn Mössbauer study of an SnO₂ electrode was performed during discharge of a lithium ion cell. The first step is lithium intercalation into the SnO₂ host structure. This lithium intercalation results in reinforcement of the SnO₂ lattice instead of direct decomposition of the oxide upon reduction. This first step is followed by the reduction of tin dioxide into unusual tin species (possibly “exotic” forms of Sn(II) or Sn(0)). The last step of the discharge consists in Li-Sn alloy formation. However, non-reduced SnO₂ is present nearly up to the end of the discharge despite a very low discharge regime. It seems highly probable that this fact is related both to slow Li diffusion and disconnection of SnO₂ particles due to Li₂O formation. The working electrode appears to be rather far from equilibrium during continuous discharge, which means that ideal succession of well-defined stages cannot describe the real phenomena involved in the operating battery.     

Low-temperature performance of LiFePO4/C cathode in a quaternary carbonate-based electrolyte

The low-temperature performance of LiFePO₄/C cathode in a quaternary carbonate-based electrolyte (1.0 M LiPF₆/EC+DMC+DEC+EMC (1:1:1:3, v/v)) was studied. The discharge capacities of the LiFePO₄/C cathode were about 134.5 mAh/g (20 °C), 114 mAh/g (0 °C), 90 mAh/g (−20 °C) and 69 mAh/g (−40 °C) using a 1C charge–discharge rate. Cyclic voltammetry measurements show obviously sluggish of the lithium insertion–extraction process of the LiFePO₄/C cathode as the operation temperature falls below −20 °C. Electrochemical impedance analyses demonstrate that the sluggish of charge-transfer reaction on the electrolyte/LiFePO₄/C interface and the decrease of lithium diffusion capability in the bulk LiFePO₄ was the main performance limiting factors at low-temperature.     

Enhanced Performance of a Lithium–Sulfur Battery Using a Carbonate‐Based Electrolyte

The lithium–sulfur battery is regarded as one of the most promising candidates for lithium–metal batteries with high energy density. However, dendrite Li formation and low cycle efficiency of the Li anode as well as unstable sulfur based cathode still hinder its practical application. Herein a novel electrolyte (1 m LiODFB/EC‐DMC‐FEC) is designed not only to address the above problems of Li anode but also to match sulfur cathode perfectly, leading to extraordinary electrochemical performances. Using this electrolyte, lithium|lithium cells can cycle stably for above 2000 hours and the average Coulumbic efficiency reaches 98.8 %. Moreover, the Li–S battery delivers a reversible capacity of about 1400 mAh g^?1_sulfur with retention of 89 % for 1100 cycles at 1 C, and a capacity above 1100 mAh g^?1_sulfur at 10 C. The more advantages of this cell system are its outstanding cycle stability at 60 °C and no self‐discharge phenomena.     

Nanostructured Carbon/Antimony Composites as Anode Materials for Lithium‐Ion Batteries with Long Life

A series of nanostructured carbon/antimony composites have been successfully synthesized by a simple sol–gel, high‐temperature carbon thermal reduction process. In the carbon/antimony composites, antimony nanoparticles are homogeneously dispersed in the pyrolyzed nanoporous carbon matrix. As an anode material for lithium‐ion batteries, the C/Sb10 composite displays a high initial discharge capacity of 1214.6 mAh g^?1 and a reversible charge capacity of 595.5 mAh g^?1 with a corresponding coulombic efficiency of 49 % in the first cycle. In addition, it exhibits a high reversible discharge capacity of 466.2 mAh g^?1 at a current density of 100 mA g^?1 after 200 cycles and a high rate discharge capacity of 354.4 mAh g^?1 at a current density of 1000 mA g^?1. The excellent cycling stability and rate discharge performance of the C/Sb10 composite could be due to the uniform dispersion of antimony nanoparticles in the porous carbon matrix, which can buffer the volume expansion and maintain the integrity of the electrode during the charge–discharge cycles.     

纳米TiO_2的电化学嵌锂研究

应用苛性钠水热法制备粒度均匀、分散性好、质子钛酸盐纳米管(直径约10～15nm).经加热烧结脱水后,该纳米管逐渐转变成具有锐钛矿相结构的纳米柱(直径约15～20nm).初步研究表明,这种具有锐钛矿相结构的纳米柱,其电化学可逆嵌/脱锂容量较高,但循环稳定性还有待改进提高.     

Anodes for lithium batteries: tin revisited

Pure tin, without the addition of conducting diluents or binders, has been evaluated as an anode in lithium cells. Capacities approaching 600 mAh/g are maintained for over 10 deep cycles, before falling off, indicating the inherent reversibility of the tin anode. These are comparable to those reported for Cu₆Sn₅ and considerably higher than for deposited tin films. The tin grain size was determined and found to decrease with cycling from over 400 to below 100 nm over 10 cycles. The cell impedance increases significantly after 10 cycles, consistent with the observed loss of capacity on extended cycling.     

LiFePO4/C composites from carbothermal reduction method

Using the cheap raw materials lithium carbonate, iron phosphate, and carbon, LiFePO₄/C composite can be obtained from the carbothermal reduction method. X-ray diffraction (XRD) and scanning electronic microscope (SEM) observations were used to investigate the structure and morphology of LiFePO₄/C. The LiFePO₄ particles were coated by smaller carbon particles. LiFePO₄/C obtained at 750 °C presents good electrochemical performance with an initial discharge capacity of 133 mAh/g, capacity retention of 128 mAh/g after 20 cycles, and a diffusion coefficient of lithium ions in the LiFePO₄/C of 8.80?×?10^?13 cm²/s, which is just a little lower than that of LiFePO₄/C obtained from the solid-state reaction (9.20?×?10^?13 cm²/s) by using FeC₂O₄ as a precursor.     

Lithium Storage in Heat‐Treated SnF2/Polyacrylonitrile Anode

Tin(II) fluoride (SnF₂) has a high Li‐storage capacity because it stores lithium first by a conversion reaction and then by a Li/Sn alloying/dealloying reaction. A polyacrylonitrile (PAN)‐bound SnF₂ electrode was heat‐treated to enhance the integral electrical contact and the mechanical strength through its cross‐linked framework. The heat‐treated SnF₂ electrode showed reversible capacities of 1047 mAh g^?1 in the first cycle and 902 mAh g^?1 after 100 cycles. Part of the excess capacity is due to lithium storage at the Sn/LiF interface, and the other part is assumed to correspond to the presence of reduced SnF₂ with protons released during the thermal cross‐linking of PAN.     

锂离子电池铜锡锑合金负极材料研究

以化学还原法制备了锂离子电池纳米铜锡锑三元合金负极材料Cu6Sn5Sb5,通过XRD、TEM和电化学测试对材料进行了表征,用非原位XRD测试方法研究了材料的贮锂机理.所制备的材料颗粒粒径大小分布在15～30nm之间.在充放电电压为1.5～OV范围内,初始可逆充电容量为595mAh/g,经过30次循环后,充电容量保持79...     

Dual-metal zeolite imidazolate framework for efficient lithium storage boosted by synergistic effects and self-assembly 2D nanosheets

Metal-organic framework materials(MOFs), such as zeolitic imidazolate framework(ZIF), have been widely used in energy storage due to their advantages such as high structural stability, large specific surface, more active sites and skeleton structures. Herein, a novel two-dimensional(2D) Co Cu-ZIF was synthesized by a facile solvothermal method. The as-prepared Co Cu-ZIF nanosheets exhibit an ultrahigh reversible capacity of 2287.4 m Ah/g and remains at 1172.1 m Ah/g after 300 cycles at a current...     

常压回流掺钴钙锰矿锂离子电池正极材料

常压回流法制备掺杂钴离子的钙锰矿,X-射线衍射(XRD)、热重(TG)、化学分析等测试表明:钙锰矿均为单一相,组成为MgxCoyMnOz·nH2O,其中0.18≤x≤0.22、0≤y≤0.24、2.10≤z≤2.53、0.35≤n≤0.73.以掺钴钙锰矿作锂离子二次电池正极材料,组成为Tod-Co10%(10%Co的Mg0.18Co0.12MnO2.19·0.45H2O)电极放电性能最佳,其首次放电比容量为219mAh/g,100次循环充放电仍有102mAh/g.对比之下,未掺钴的Tod-Co0%电极(钙锰矿)首次放电比容量为211mAh/g,30次循环后为37mAh/g.     

Continuous supercritical hydrothermal synthesis: lithium secondary ion battery applications

Nanosized lithium iron phosphate (LiFePO₄) and transition metal oxide (MO, where M is Cu, Ni, Mn, Co, and Fe) particles are synthesized continuously in supercritical water at 25?C30?MPa and 400??C under various conditions for active material application in lithium secondary ion batteries. The properties of the nanoparticles, including crystallinity, particle size, surface area, and electrochemical performance, are characterized in detail. The discharge capacity of LiFePO₄ was enhanced up to 140?mAh/g using a simple carbon coating method. The LiFePO₄ particles prepared using supercritical hydrothermal synthesis (SHS) deliver the reversible and stable capacity at a current density of 0.1?C rate during ten cycles. The initial discharge capacity of the MO is in the range of 800?C1,100?mAh/g, values much higher than that of graphite. However, rapid capacity fading is observed after the first few cycles. The continuous SHS can be a promising method to produce nanosized cathode and anode materials.