锂离子蓄电池负极导电剂的研究

Research on conductive material for negative electrode in lithium ion batteries

用扫描电子显微镜(SEM)考察了3种导电剂粉体材料的形貌,通过测定3种导电剂材料的吸水能力,研究了导电剂的振实密度与吸液能力的关系。结果表明,导电剂的振实密度越大,其吸液能力越小;反之则其吸液能力越大。利用恒流充放电、循环伏安技术考察了3种导电剂的贮锂性能,实验表明石墨类导电剂(KS、SO)具有一定的贮锂性能,但其首次库仑转换效率低;而炭黑类导电剂(SP)仅起导电作用。利用六西格玛(简称6σ)混合设计考察了导电剂之间的交互作用,及3种导电剂配比对石墨电极放电比容量的影响,当质量比m(包覆石墨)∶m[导电剂(KS+SP)]∶m(PVDF)=92∶3∶5且m(KS)∶m(SP)=1.66∶1时,电极放电比容量可以稳定地达到315mAh·g-1以上。

The morphology of three conductive material, including KS, SP, SO, were analyzed using scanning electron microscope （SEM）. The relationship between the tap density and liquid uptake volume of the conductive materials was studied by measuring water absorbability. The results showed the liquid uptake volume decreased with the increase of its tap density. The characteristics of storage lithium of three conductive materials were studied by using cyclic voltammetry technique and constant current charge-discharge method. The result showed graphite conductive material（KS,SO） exhibited electrochemical storage lithium capacity with low coulombic efficiency at first cycle, while carbon black conductive material（SP） only had conductive effect. The interaction of conductive materials and influence of conductive materials proportions on the discharge specific capacity of graphite electrode were investigated by 6 σ mixture experiments.