摘要
随着锂离子电池向高比能量方向发展,传统的石墨负极材料将逐渐被合金、金属氧化物等高比容量负极材料所取代。高比容量负极材料在循环过程中易产生较大的体积变化,从而导致电极循环性能衰退,限制了其实际应用。除从材料本身入手外,变换粘结剂是改善高比容量负极材料电化学性能的有效途径。本文对近十年来锂离子电池高比容量负极用粘结剂的发展进行了总结。对聚偏氟乙烯(PVDF)粘结剂进行改性处理,提高其黏弹性,可以显著改善电极的电化学性能。与PVDF相比,水性羧甲基纤维素(CMC)粘结剂可以明显提高Si基电极的电化学性能。CMC用作高比容量负极材料粘结剂明显优于PVDF的原因包括其利于电极浆料分散、与电解液不反应以及能够与活性物质之间形成化学键(共价键或氢键)等。同时,CMC本身的结构参数(分子量、取代度、阳离子)、CMC加入量、浆料pH值及电极孔隙率均对CMC电极的性能具有重要影响。聚丙烯酸(PAA)及海藻酸钠粘结剂由于含有更多的羧基(—COOH)基团,对高比容量负极材料具有更好的效果。其他新型粘结剂在高比容量负极性能的提升方面也具有较大潜力。
With the development of lithium ion batteries with high energy density, the traditional graphite anode material will be replaced gradually by other materials with high specific capacity, such as alloy and metal oxides. However, these high capacity anode materials suffer from huge volume change during the cycling process, which causes the degradation of cycle performance and thus limits their application. Apart from the improvement on the active materials, the rational choice of binder is an effective way to improve the electrochemical performance of electrode. In the present paper, the development of binders used in high capacity anode in the recent decade is reviewed. With various modifications on polyvinylidene fluoride （PVDF） binder to enhance its viscoelasticity, the electrochemical properties of electrode can be improved. Compared to PVDF, the water-based carboxymentyl cellulose （CMC） binder can enhance greatly the electrochemical performance of Si-based electrodes. Better dispersion of electrode slurry, inactive to electrolyte and forming a chemical bond （covalent or hydrogen bonding） with active materials are the reasons for CMC being better than PVDF when used in the high capacity negativeelectrode. The structural parameters of CMC （molecular weight, degree of substitution, cationic） , CMC content, pH value of the slurry and the electrode porosity have important influence on CMC electrode performance. Besides, polyacrylic acid （PAA） and Na-alginate binder are much effective in improving the cycling performance of high capacity electrode, due to their high carboxyl groups （--COOH）. Other novel binders also have potential to enhance cycling performance of high capacity electrode.
出处
《化学进展》
SCIE
CAS
CSCD
北大核心
2013年第8期1401-1410,共10页
Progress in Chemistry
基金
国家自然科学基金项目(No.21273019)
国家重点基础研究发展计划(973)项目(No.2013CB934003)
上海市科技人才计划项目(No.12XD1421900)
上海市科委专项项目(No.10dz2250900)
上海市科委科技创新项目(No.12dz1200503)资助
关键词
粘结剂
高比容量负极
聚偏氟乙烯
羧甲基纤维素
聚丙烯酸
海藻酸钠
锂离子电池
binder
high capacity anode
polyvinglidene fluoride （PVDF）
carboxymethyl cellulose（CMC）
polyacrylic acid （PAA）
Na-alginate
lithium-ion battery
