Ceramic and polymeric solid electrolytes for lithium-ion batteries

Lithium-ion batteries are important for energy storage in a wide variety of applications including consumer electronics, transportation and large-scale energy production. The performance of lithium-ion batteries depends on the materials used. One critical component is the electrolyte, which is the focus of this paper. In particular, inorganic ceramic and organic polymer solid-electrolyte materials are reviewed. Solid electrolytes provide advantages in terms of simplicity of design and operational safety, but typically have conductivities that are lower than those of organic liquid electrolytes. This paper provides a comparison of the conductivities of solid-electrolyte materials being used or developed for use in lithium-ion batteries.     

锂离子电池用（聚）离子液体电解质

锂离子电池已广泛应用于便携式电子设备和电动汽车等领域,然而商用锂离子电池中含有大量易燃的碳酸酯类有机溶剂,容易造成安全隐患。离子液体具有蒸汽压低、化学结构设计多样性、热稳定性及电化学稳定性优异等优点,可以用来代替易燃有机溶剂,在电化学储能领域具有广阔的应用前景。聚离子液体是一类聚合物重复单元上含有阴、阳离子的新型聚合物电解质材料,兼具离子液体和聚合物固态电解质不漏液、易于加工的优势。根据离子液体和聚离子液体化学结构的设计合成及其在锂离子电池中的应用形式,综述了近年来离子液体电解质的研究进展,并提出了离子液体电解质未来的应用挑战和发展方向。     

Research on key materials for potassium ion batteries

钾具有资源丰富、价格低廉以及较低的电化学电势的特点,利用其开发的钾离子电池具有低成本、长寿命、能量密度高等特点,可满足储能领域需要。然而,钾离子半径大和质量大,给电池电极材料与电解质材料开发提出新的挑战。近年来,在电动汽车与储能应用等重大需求的牵引下,人们对钾离子电池的高容量电极材料和电解液进行了大量的研究工作。其中普鲁士蓝及其类似物、过渡金属氧化物和聚阴离子材料等正极材料展现了应用前景;负极材料主要包括碳基、钛基和合金类材料;电解质材料有酯类电解质和醚类电解质,这些研究成果为钾离子电池的基础与应用研究提供了重要的指导意义。     

Electrode and electrolyte materials for electrochemical capacitors

Among different electric energy storage technologies electrochemical capacitors are used for energy storage applications when high power delivery or uptake is needed. Their energy and power densities, durability and efficiency are influenced by electrode and electrolyte materials however due to a high cost/performance ratio; their widespread use in energy storage systems has not been attained yet.Thanks to their properties such as high surface area, controllable pore size, low electrical resistance, good polarizability and inertness; activated carbons derived from polymeric precursors are the most used electrode materials in electrochemical capacitors at present. Other electrode materials such as shaped nano-carbons or metal oxides are also investigated as electrode materials in electrochemical capacitors, but only as useful research tools.Most commercially used electrochemical capacitors employ organic electrolytes when offering concomitant high energy and high power densities. The use of aqueous based electrolytes in electrochemical capacitor applications is mainly limited to research purposes as a result of their narrow operating voltage. Recent studies on room temperature ionic liquids to be employed as electrolyte for electrochemical capacitor applications are focused on fine tuning their physical and transport properties in order to bring the energy density of the device closer to that of batteries without compromising the power densities.In this paper a performance analysis, recent progress and the direction of future developments of various types of materials used in the fabrication of electrodes for electrochemical capacitors are presented. The influence of different types of electrolytes on the performance of electrochemical capacitors such as their output voltage and energy/power densities is also discussed.     

C,N co-doped Co3O4 hollow spheres prepared via hydrothermal reaction for improved electrochemical activity

Superior electrode materials play a key role on the electrochemical performance for the lithium-ion batteries and supercapacitors. The Co₃O₄-based materials are promising electrode materials due to their high specific capacity and energy density. However, the poor cycle performance limits their applications during the process of the commercialization for the lithium-ion batteries and supercapacitors. Because of the poor cycle stability, C, N co-doped Co₃O₄ hollow spheres are successfully prepared and used as electrode materials for the lithium-ion batteries and supercapacitors. Via the C, N co-doping process, the electronic conductivity is greatly improved. Moreover, the hollow structure could ensure the structural stability during the electrochemical process. As a result, the cycle performance and specific capacity are greatly improved when the C, N co-doped Co₃O₄ composites are used as electrode materials for the lithium-ion batteries and supercapacitors.     

A study of tri(ethylene glycol)-substituted trimethylsilane (1NM3)/LiBOB as lithium battery electrolyte

Silicon-based electrolyte has emerged as a primary candidate for the development of large lithium-ion batteries for electric vehicle (EV) and other systems in which safety is a primary consideration. Comparing to the electrolyte used in the conventional lithium-ion batteries, which are flammable, volatile, and highly reactive organic carbonate solvents, silicon-based electrolytes are thermally and chemically stable, less flammable and environmental benign. Tri(ethylene glycol)-substituted trimethylsilane (1NM3) was identified as a focus of investigation due to its high conductivity and low viscosity. We present the results of a systematic investigation of the 1NM3-based electrolytes with lithium bis(oxalate)borate (LiBOB) salt, including temperature dependent ionic conductivity and lithium cell performance. Lithium-ion cell with LiNi_1/3Co_1/3Mn_1/3O₂ as the positive electrode and MAG graphite as the negative electrode has shown excellent cyclability using 1NM3-LiBOB as electrolyte.     

Research progress on lithium based Water-in-salt electrolytes

与传统的商用有机锂离子电池相比,水系锂离子电池具有高安全性、成本低、环境友好等优点,但由于水的热力学窗口较窄（1.23 V）,从而大大限制了其输出电压和能量密度。Water-in-salt电解液的提出将水溶液的电化学窗口拓宽到3.0 V以上,为实现新型高电压水系锂离子电池提供了有利前提保证。本综述意在介绍Water-in-salt电解液及其相关衍生体系以及其在锂离子电池、锂硫电池以及混合离子电池中的相关应用拓展。与此同时,对该新体系中所引出的新的基础科学问题,包括水系固态电解质界面（SEI）膜的生长机理及锂离子的传输机制做了简单归纳和总结。     

Graft copolymer-based lithium-ion battery for high-temperature operation

The use of conventional lithium-ion batteries in high temperature applications (>50 °C) is currently inhibited by the high reactivity and volatility of liquid electrolytes. Solvent-free, solid-state polymer electrolytes allow for safe and stable operation of lithium-ion batteries, even at elevated temperatures. Recent advances in polymer synthesis have led to the development of novel materials that exhibit solid-like mechanical behavior while providing the ionic conductivities approaching that of liquid electrolytes. Here we report the successful charge and discharge cycling of a graft copolymer electrolyte (GCE)-based lithium-ion battery at temperatures up to 120 °C. The GCE consists of poly(oxyethylene) methacrylate-g-poly(dimethyl siloxane) (POEM-g-PDMS) doped with lithium triflate. Using electrochemical impedance spectroscopy (EIS), we analyze the temperature stability and cycling behavior of GCE-based lithium-ion batteries comprised of a LiFePO₄ cathode, a metallic lithium anode, and an electrolyte consisting of a 20-μm-thick layer of lithium triflate-doped POEM-g-PDMS. Our results demonstrate the great potential of GCE-based Li-ion batteries for high-temperature applications.     

Synthesis of composite electrode materials of FeOOH-based particles/carbon powder and their high-rate charge-discharge performance in lithium cells

Composite electrode materials of FeOOH-based particles and carbon powder were prepared with and without heat treatment of composite powder. The composite powder was obtained by hydrolyzing mixed aqueous solutions of FeCl₃, Ti(SO₄)₂ and electron conducting carbon powder as acetylene black (AB) or Ketjen black (KB). FeOOH-based materials formed in the presence of Ti(IV) ions became amorphous and/or low crystalline structure. The composite powder worked as lithium insertion electrode materials in lithium cells using nonaqueous electrolytes including lithium ions. The electrodes exhibited a good cycle performance at large charge-discharge current densities over 5 mA cm⁻² (4 A g⁻¹ per weight of active material). In addition, it was found that the cycle performance was effective process to be improved by the heat treatment of the composite materials. The composite materials such as amorphous FeOOH, α-Fe₂O₃, TiO₂ and electron conductive powder obtained by the heat treatment are one of the promising candidates as electrode materials for energy storage devices, such as lithium-ion batteries and hybrid electrochemical supercapacitors.     

Economic analysis for room-temperature sodium-ion battery technologies

随着人们对新能源和环境的重视,锂离子电池的应用逐渐扩展到电动汽车和储能领域,这势必增加了锂资源的使用和消耗.在锂资源日益紧缺的形势下,锂离子电池原材料成本必然难以降低,使其在大规模储能中的应用受到限制.而室温钠离子电池由于其资源丰富,成本低,能量转换效率高,循环寿命长,维护费用低等诸多优势已成为目前研究的热点.本文对室温钠离子电池材料选择和原材料成本进行了分析,并与当前常用的锂离子电池体系进行对比,从电池经济性角度表明室温钠离子电池是大规模储能领域的优秀备选电池.     

Research on properties of cathode materials of aqueous zinc-lithium flow batteries

近年来,水系锂离子电池具有功率高、环境污染小等优点而受到广泛关注。文章采用在碱性体系中稳定性较好的LiFePO₄作为正极材料,石墨板为负极,组装锌锂离子电池;通过SEM分析、XRD分析、循环伏安测试、线性扫描伏安测试等手段研究了锂的嵌入脱出以及锌的沉积溶解反应的反应活性及正极材料的稳 定性。     

Graphite materials prepared by HTT of unburned carbon from coal combustion fly ashes: Performance as anodes in lithium-ion batteries

The behaviour as the potential negative electrode in lithium-ion batteries of graphite-like materials that were prepared by high temperature treatment of unburned carbon concentrates from coal combustion fly ashes was investigated by galvanostatic cycling. Emphasis was placed on the relation between the structural/morphological and electrochemical characteristics of the materials. In addition, since good electrode capacity retention on cycling is an important requirement for the manufacturing of the lithium-ion batteries, the reversible capacity provided by the materials prepared on prolonged cycling (50 cycles) was studied and the results were compared with those of petroleum-based graphite which is commercialized as anodic material for lithium-ion batteries. The graphite-like materials prepared lead to battery reversible capacities up to ∼310 mA hg⁻¹ after 50 cycles, these values were similar to those of the reference graphite. Moreover, they showed a remarkable stable capacity along cycling and low irreversible capacity. Apparently, both the high degree of crystallinity and the irregular particle shape with no flakes appear to contribute to the good anodic performance in lithium-ion batteries of these materials, thus making feasible their utilization to this end.     

Applications of carbon nanotubes in the lithium-ion batteries

碳纳米管因具有优异的电导率、热导率、力学性能以及独特的结构形貌,被用于改进锂离子电池性能。该文总结了近年来碳纳米管作为锂离子电池的添加剂、电极材料复合基体以及集流体的最新研究进展,重点介绍了最新的碳纳米管作为电极材料添加剂的使用方法、碳纳米管与电极材料的不同复合方法及其对锂离子电池容量性能、倍率性能以及循环寿命的影响。同时指出了碳纳米管在锂离子电池中大规模应用时需要克服的问题,如降低碳纳米管的制备成本、开发适用于工业生产的复合技术、改善碳纳米管的分散性能等。     

单离子导体聚合物电解质研究进展

聚合物电解质能够避免传统液态电解液漏液的隐患,抑制锂枝晶的生长,提高电池的安全性能。单离子导体是一类锂离子迁移数接近1的聚合物电解质,能有效避免阴离子移动产生浓差极化,降低内部阻抗,从而提高锂电池的容量以及循环性能,成为近年来聚合物电解质的研究热点。本文综述了单离子导体聚合物电解质的研究进展,尤其关注离子电导率和锂离子迁移数较高的体系,并探讨了单离子导体聚合物电解质所面临的挑战以及发展前景。     

Energy-storage technologies and electricity generation

As the contribution of electricity generated from renewable sources (wind, wave and solar) grows, the inherent intermittency of supply from such generating technologies must be addressed by a step-change in energy storage. Furthermore, the continuously developing demands of contemporary applications require the design of versatile energy-storage/power supply systems offering wide ranges of power density and energy density. As no single energy-storage technology has this capability, systems will comprise combinations of technologies such as electrochemical supercapacitors, flow batteries, lithium-ion batteries, superconducting magnetic energy storage (SMES) and kinetic energy storage. The evolution of the electrochemical supercapacitor is largely dependent on the development of optimised electrode materials (tailored to the chosen electrolyte) and electrolytes. Similarly, the development of lithium-ion battery technology requires fundamental research in materials science aimed at delivering new electrodes and electrolytes. Lithium-ion technology has significant potential, and a step-change is required in order to promote the technology from the portable electronics market into high-duty applications. Flow-battery development is largely concerned with safety and operability. However, opportunities exist to improve electrode technology yielding larger power densities. The main barriers to overcome with regard to the development of SMES technology are those related to high-temperature superconductors in terms of their granular, anisotropic nature. Materials development is essential for the successful evolution of flywheel technology. Given the appropriate research effort, the key scientific advances required in order to successfully develop energy-storage technologies generally represent realistic goals that may be achieved by 2050.     

锂电池用全固态聚合物电解质的研究进展

目前大规模商业化的锂二次电池普遍采用有机碳酸酯类的液态电解质,易泄露、易燃烧、易爆炸等安全问题限制了该类电解质的进一步应用。全固态聚合物电解质（all-solid-state polymer electrolytes,ASPEs）电池具有安全性能好、能量密度高、工作温度区间广、循环寿命长等优点,是锂离子电池领域的研究热点之一。ASPEs通常还具有优异的力学性能,可以很好地抑制锂金属电极在充放电过程中的枝晶生长,所以在锂金属电池领域也具有十分重要的应用前景。作者综述了研究较多的几种ASPEs体系,包括聚氧化乙烯（PEO）基体系、聚碳酸酯基体系、聚硅氧烷基体系、聚合物锂单离子导体体系。PEO基ASPEs是研究最早且研究最多的一类ASPEs材料,但其高结晶性造成室温Li+迁移困难、离子电导率低等问题,所以研究人员研发了一系列降低PEO结晶度、提升体系离子电导率的改性手段。聚碳酸酯基ASPEs主链结构中含有强极性碳酸酯基团而且室温无定形态,使得锂盐更容易解离,且室温离子电导率一般较PEO基要高,是比较有潜力的PEO基ASPEs替代材料。除了碳链聚合物,玻璃化转变温度较低的聚硅氧烷基ASPEs体系也因为其较高的离子电导率受到研究人员关注。在锂电池充放电过程中,Li+才是有效载荷子,电解质中阴离子的迁移会增加电解质体系的浓差极化,所以阴离子不发生迁移、Li+迁移数接近于1的聚合物锂单离子导体也是一类具有研究价值的ASPEs材料。最后,本综述讨论了全固态聚合物电解质的应用前景及未来发展方向,指出了PEO基体系的研究重点在于发展有机-无机复合体系、聚碳酸酯基体系的研究重点在于发展与其它聚合物的共混体系、聚硅氧烷基体系的研究重点在于增强体系力学性能、聚合物锂单离子导体体系的研究重点在于设计离子电导率更高的新型聚阴离子锂盐。     

Research progress on electrolyte additives for high voltage lithium-ion batteries

普通锂离子电池在高电压下的氧化分解限制了高压锂离子电池的发展,为了解决这一问题,可以设计、合成新型的耐高压电解液;寻找合适的电解液添加剂,然而从经济效益考虑,发展合适的电解液添加剂来稳定电极/电解液界面更加受到研究者们的青睐。本文综述了最近几年在高压锂离子电池电解液添加剂方面的研究进展,并按照添加剂的种类将其分为6部分进行探讨：含硼类添加剂、有机磷类添加剂、碳酸酯类添加剂、含硫添加剂、离子液体添加剂及其它类型添加剂。分别对这些添加剂的作用机理、作用效果进行了阐述,展望了添加剂在高压锂离子电池中的发展前景及未来研究方向。     

金属有机框架及其衍生金属氧化物在锂和钠离子电池中的应用

高性能锂和钠离子电池是未来便携电子设备、电动汽车和大规模储能电站的重要组成部分,受到了各行业的广泛关注。目前商用的锂离子电池和研发中的钠离子电池都面临着一些技术瓶颈,主要表现为能量密度低、充放电慢等,导致无法满足市场的需求。具有独特结构、高比表面积的金属有机框架及其衍生金属氧化物可作为电化学储能器件新型电极材料,满足高性能锂和钠离子电池的要求。本文综述了近年来金属有机框架及其衍生金属氧化物作为锂和钠离子电池电极材料的研究进展,同时指出了金属有机框架及其衍生金属氧化物在实际应用中的不足及未来可能的一些改进措施。     

Ionic liquids as electrolytes for Li-ion batteries—An overview of electrochemical studies

The paper reviews properties of room temperature ionic liquids (RTILs) as electrolytes for lithium and lithium-ion batteries. It has been shown that the formation of the solid electrolyte interface (SEI) on the anode surface is critical to the correct operation of secondary lithium-ion batteries, including those working with ionic liquids as electrolytes. The SEI layer may be formed by electrochemical transformation of (i) a molecular additive, (ii) RTIL cations or (iii) RTIL anions. Such properties of RTIL electrolytes as viscosity, conductivity, vapour pressure and lithium-ion transport numbers are also discussed from the point of view of their influence on battery performance.     

Interpretation of the electrode binder standard for lithium ion battery

电极黏结剂是锂离子电池的重要辅助功能材料之一,虽然本身没有容量,但却是维持电极完整性的关键,决定了电极涂层的附着力和电极的柔韧性,并会影响到电极浆料的流变特性等工艺性能。本文主要分析了与电极黏结剂相关的国内标准,对锂离子电池电极黏结剂的相关特性和测试方法进行了介绍,并对未来电极黏结剂标准的制定提出了建议。