Conjugated carbonyl compounds as electrode materials for sodium-ion/potassium-ion batteries

钠（钾）离子电池资源丰富、成本低廉,是极具大规模应用潜力的新型电池体系。然而,受制于较大的钠（钾）离子半径,这两类电池电极材料的选择受到了极大的限制。以共轭羰基化合物为代表的有机电极材料具有柔性的骨架结构,对阳离子半径选择性小,且结构多样、理论比容量高、环境友好,基于有机共轭羰基化合物构建的钠（钾）离子电池是未来“绿色电池”发展的重要方向。本文介绍了共轭羰基化合物的分类、储钠/钾性能及机理,重点探讨了羰基化合物作为储钠（钾）材料存在的问题和改进方法。最后,总结了羰基化合物作为钠钾离子电池电极材料存在的基础科学问题、技术挑战以及竞争力,同时进一步展望了有机共轭羰基化合物的发展方向以及大规模储能领域的应用前景。     

The cycle life investigation for spinel LiNi0.5Mn1.5O4 full cells

分别以石墨和钛酸锂为负极活性物质,制备了尖晶石镍锰酸锂的32131型圆柱锂离子电池.石墨负极电池和钛酸锂负极电池容量分别为7.5 A·h和5.5 A·h,质量能量密度分别达到152 W·h/kg和81 W·h/kg.常温充放电循环测试结果表明,石墨和钛酸锂两种负极体系电池循环寿命将分别达到400次和1000次,这种循环寿命的差别主要体现在负极上,即正极材料中溶解的Mn在石墨负极表面沉积并持续催化SEI膜生成,减少了电池中可使用的活性Li⁺,进而导致电池寿命快速衰减;相比而言,钛酸锂负极表面不存在明显SEI,同时正极过量设计电池也使得钛酸锂体系电池的镍锰酸锂与电解液间的界面副反应低于石墨体系的负极过量设计电池.     

Application of tetrasodium salt of 3, 4, 9, 10-perylenetetracarboxylic acid for Li ion batteries

共轭羰基化合物由于其良好的离子和电子传输性能以及高度的可逆性,成为研究最为广泛的一类有机电极材料。采用具有3,4,9,10-苝四甲酸二酐为前驱体与氢氧化钠反应制备了3,4,9,10-苝四甲酸四钠盐（Na₄C₂₄H₈O₈,Na-PTCA）,作为锂离子电池的负极材料。Na-PTCA在50 mA/g的电流密度电压区间0.01~2 V条件下,循环100圈后还能保持468 mA·h/g的容量,表现出良好的循环稳定性。同时,其羧基部分在约1.10/1.38 V的电压平台表现高度的循环可逆性,在循环100圈后容量保持为148 mA·h/g。这些结果对扩展新型高比容锂离子电池负极材料提供了一种有效的设计思路。     

石墨烯包封Na3V2(PO4)3用作钠离子电池负极材料的电化学性能探究

具有三维网络结构的NASICON型Na₃V₂(PO₄)₃材料,由于其稳定的电压平台,较高的理论容量(117 mA·h/g),被视为一种具有良好应用前景的钠离子电池负极材料。采用溶剂热和进一步热处理的方式,获得石墨烯包封Na₃V₂(PO₄)₃的复合材料[Na₃V₂(PO₄)₃/G],有效提高了Na₃V₂(PO₄)₃的电子导电性。在0.01～3.00 V电压区间,0.2 C倍率进行测试时,Na₃V₂(PO₄)₃/G复合材料在230圈循环后,其放电比容量保持在100.9 mA·h/g,容量保持率高达68.4%,即使在5 C倍率,其放电比容量仍可达65.2 mA...     

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。     

Recent research progress of metal compounds as anode materials for sodium-ion batteries

钠离子电池具有钠资源存储丰富、价格低廉等优点,是一种极具发展前景的储能装置,因此成为当下研究热点。钠离子电池的电化学性能主要取决于正负极材料。但是,钠离子较大的半径使其在电极材料中可逆地嵌入/脱出更为困难。而金属化合物材料作为储钠负极材料时,遵循转化反应机制,并表现出较高的理论比容量,因而受到研究人员的广泛关注。本文综述了金属氧化物、金属硫化物、金属磷化物等几种金属化合物负极材料的储钠机制和研究进展,探讨了金属化合物材料的储钠性能,阐明了金属化合物作为理想的储钠负极材料的优势,最后对金属化合物材料的研究前景进行了展望。     

Preparation and electrochemical performance of LiFePO4/S composite cathode materials

以提高磷酸铁锂体系动力电池的能量密度为目的,在LiFePO₄正极材料中加入少量S材料球磨制得LiFePO₄/S复合正极材料。使用X射线衍射（XRD）和扫描电子显微镜（SEM）表征了结构和形貌,并分别组装扣式电池和软包电池测试其电化学性能。结果表明,磷酸铁锂纳米颗粒致密均匀附着在硫材料表面,构成具有包覆性结构的复合材料。在不同比例的LiFePO₄/S复合材料中,硫的添加量为15%的LiFePO₄/S复合正极材料表现出最优异的电化学性能,0.1 C下的初始容量为251.5mA·h/g,循环100周之后容量保持率达94.9%。以该比例的复合材料为正极的0.5A·h软包电池,循环100周后容量保持率为86.7%。LiFePO₄作为一种极性载体,对多硫化物有一定的吸附能力,少量硫的加入可以在大幅度提高LiFePO₄材料放电容量的同时,维持优异的循环稳定性。LiFePO₄/S复合材料可为磷酸铁锂体系动力电池的发展提供新的思路。     

Thermodynamic calculation on energy densities of multi-electron transfer Mg/Al batteries

镁离子电池和铝离子电池因其高能量密度、地壳储量丰富、安全等优良特性有望成为下一代新型高能量密度储能体系,是未来二次电池研究的热点之一。本文采用热力学方法计算和分析了近300种镁离子和铝离子电池体系的理论质量能量密度、体积能量密度和电压。在所得数据的基础上,以目前商业化锂离子电池正极材料钴酸锂为对比参考,综合考虑质量能量密度、体积能量密度、标准电极电位、毒性、腐蚀性、易燃性、环境友好性等诸多因素,逐步筛选出符合条件的一系列镁离子正极材料（O₂、S、MnO₂、MoO₃、Fe₂O₃、Fe₃O₄、NiO、MoO₂、CuO、Cu₂O）和铝离子的正极材料（O₂、S、MnO₂、MoO₃、NiO、CuO、Cu₂O）。     

钛酸锂基锂离子电池及其健康状态研究进展

锂离子电池的高功率密度和高能量密度等特性使其成为电动汽车能源和新能源电网储能的重要载体。功率性能和安全特性是锂离子电池发展的两个主要挑战。钛酸锂Li₄Ti₅O₁₂材料因具有良好的结构稳定性、安全性能、长循环寿命、高功率特性和高低温放电性能,被认为是锂电池负极材料的良好备选。综述了以钛酸锂材料为负极的锂离子电池的相关工作,介绍了钛酸锂材料的结构、电化学特性、制备方法和作为电池负极材料面临的主要问题,重点介绍了钛酸锂负极电池的全电池性能和健康状态研究等方面。     

MW-assisted synthesis of LiFePO4 for high power applications

LiFePO₄/C was prepared by solid-state reaction from Li₃PO₄, Fe₃(PO₄)₂·8H₂O, carbon and glucose in a few minutes in a scientific MW (microwave) oven with temperature and power control. The material was characterized by X-ray diffraction, scanning electron microscopy and by TGA analysis to evaluate carbon content. The electrochemical characterization as positive electrode in EC (ethylene carbonate)–DMC (dimethylcarbonate) 1 M LiPF₆ was performed by galvanostatic charge–discharge cycles at C/10 to evaluate specific capacity and by sequences of 10 s discharge–charge pulses, at different high C-rates (5–45C) to evaluate pulse-specific power in simulate operative conditions for full-HEV application. The maximum pulse-specific power and, particularly, pulse efficiency values are quite high and make MW synthesis a very promising route for mass production of LiFePO₄/C for full-HEV batteries at low energy costs.     

Fabrication of layered structure VS4 anchor in 3D graphene aerogels as a new cathode material for lithium ion batteries

VS₄ has gained more and more attention for its high theoretical capacity (449 mAh/g with 3e⁻ transfer) in lithium ion batteries (LIBs). Herein, a layered structure VS₄ anchored in graphene aerogels is prepared and first reported as cathode material for LIBs. VS₄@GAs composite exhibits an exceptional high initial reversible capacity (511 mAh/g), an excellent high-rate capability (191 mAh/g at the 5 C), and an excellent cyclic stability (239 mAh/g after 15 cycles).     

Amorphous carbon anode with controllable pores for rechargeable lithium-ion battery

为满足储能市场对高功率电池的需求,开发兼具高容量和高功率性能的锂离子电池负极材料成为必然趋势。本文通过改变煤基沥青在碳化过程中的空速,考察其对无定形碳材料结构的影响,提高煤基沥青无定形碳材料的电化学性能。应用X射线粉末衍射（XRD）、拉曼（Raman）、N₂吸附-脱附和扫描电镜对所制备的无定形碳材料进行结构表征。通过比容量、库仑效率、倍率、循环性能评判材料的电化学性能。结果表明：可以通过改变气体空速来调控无定形碳材料的孔道和碳层无定形度,实现同步提升容量和倍率性能的效果。当气体空速≥0.5 m/min时,充电容量可达近260 mA·h/g,2C充电容量可达约137 mA·h/g。     

Preparation and lithium storage performances of g-C3N4/Si nanocomposites as anode materials for lithium-ion battery

As the anode material of lithium-ion battery, silicon-based materials have a high theoretical capacity, but their volume changes greatly in the charging and discharging process. To ameliorate the volume expansion issue of silicon-based anode materials, g-C₃N₄/Si nanocomposites are prepared by using the magnesium thermal reduction technique. It is well known that g-C₃N₄/Si nanocomposites can not only improve the electronic transmission ability, but also ameliorate the physical properties of the material for adapting the stress and strain caused by the volume expansion of silicon in the lithiation and delithiation process. When g-C₃N₄/Si electrode is evaluated, the initial discharge capacity of g-C₃N₄/Si nanocomposites is as high as 1033.3 mAh/g at 0.1 A/g, and its reversible capacity is maintained at 548 mAh/g after 400 cycles. Meanwhile, the improved rate capability is achieved with a relatively high reversible specific capacity of 218 mAh/g at 2.0 A/g. The superior lithium storage performances benefit from the unique g-C₃N₄/Si nanostructure, which improves electroconductivity, reduces volume expansion, and accelerates lithium-ion transmission compared to pure silicon.     

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 rechargeable lithium battery employing a porous thin film of Cu3+δMo6S7.9

Porous, thin films of copper molybdenum sulfides (Cu_3+δMo₆S_7.9), that have been prepared by the technique of painting and subsequent reaction with mixed H₂/H₂S gases at 500 °C, have been used as a cathode material for lithium secondary batteries. The test cell comprised: Li/2 M LiClO₄ in PC-THF (4:6)/Cu_3+δMo₆S_7.9 (porous, thin film). The discharge reaction proceeded via the intercalation of lithium ions into the structural interstices of the cathode material.

The first discharge curve of the cell showed that the porous film could incorporate up to 18 lithium ions per formula unit. The capacity of the thin film was four times higher than that previously reported for powder or pressed-pellet electrodes. The theoretical energy density was 675 W h kg⁻¹, i.e., higher than that of TiS₂ (455 W h kg⁻¹) which is one of the best materials for high-energy lithium batteries. From X-ray diffraction studies of the lithium incorporated in the thin film at each discharge step, it is suggested that there are four incorporation reactions of lithium ions into the cathode. Finally, cycling tests have been conducted at room temperature.     

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。     

Testing of the performance and energy-storage applied for retired LiFePO4 batteries

针对某电动公交车退役LiFePO₄动力电池,测试了电池的容量、直流内阻、常温下的储存性能,进而测试电池的倍率充放电性能、高低温特性和循环性能,分析了新旧电池相关参数的差异及变化规律;在此基础上,重组电池模组,测试其循环性能;最后集成了1MW·h梯次利用电池储能系统并参与风电平滑。结果显示,该动力电池容量衰退初始容量75%左右时,直流内阻只有小幅增加,电池常温下的储存性能、倍率性能、高低温性能下降不显著,电池单体和模块的循环性能良好,显示出该退役LiFePO₄电池具有较好的梯次利用价值。     

Preparation and electrochemical performance of MnFe2O4 with porous rod structure based on micro-emulsion synthesis

本工作以硫酸亚铁和乙酸锰为原料,在表面活性剂双（2-乙基己基）琥珀酸酯磺酸钠气溶胶作用下,通过微乳液法合成了前体,锻烧后得到了具有多孔结构的一维棒状MnFe₂O₄材料。棒直径约200 nm、长度2~3 μm,含有大量孔径在13~35 nm的介孔结构。将制备的MnFe₂O₄作为锂离子电池负极材料,进行电化学性能测试,在100 mA/g的电流密度下200圈循环仍能保持630 mA·h/g以上的容量,同时也具有良好的倍率性能。研究显示多孔棒状MnFe₂O₄是一种具有应用前景的锂离子电池负极材料。     

Research status of iron based fluoride cathode materials for lithium ion battery

随着新能源技术的不断发展,对锂离子电池的能量密度要求越来越高。氟化铁（FeF₃）和氟化亚铁（FeF₂）因具有较小的分子量、多电子转化反应及高电压等优点正成为极具发展潜力的高比能锂电正极材料,但是导电性差、转化反应使得材料需要较大过电势,这制约了其实际应用。本文首先介绍了FeF₃和FeF₂的基本性质及储锂机制,随后具体论述了两者的电化学性能改进措施,主要包括对FeF₃和FeF₂进行晶体结构扩展和元素替换而出现的很多铁基氟化物新相（氟化铁的水合物Fe_xF_y·mH₂O、氟氧化铁FeOF）,纳米多孔结构的设计,碳纳米复合材料构建的研究,并简要展望了未来的发展方向。     

二氟磷酸锂作为电解液添加剂在锂离子电池中的应用

锂离子电池的能量密度主要由正、负极材料的比容量和电极电位决定,但其性能发挥与电极/电解液界面性质密切相关。为提高锂离子电池的性能,必须使用电解液添加剂改善电极/电解液界面性质。迄今为止,已有大量的文献报道各种类型的电解液添加剂,但得到实际应用的却为数不多。二氟磷酸锂（LiPO₂F₂）是最近得到实际应用的电解液添加剂,能有效降低界面阻抗、提高充放电循环稳定性等。本文介绍该添加剂在锂离子电池中的应用效果及其作用机理。