含碳纳米管导电剂改善Li_4Ti_5O_(12)电极电化学性能

采用一种较为实用的调浆方法,考察了碳纳米管与乙炔黑的复合物(CNTs/AB)导电剂、乙炔黑(AB)导电剂和碳纳米管(CNTs)导电剂对Li_4Ti_5O_(12)电化学性能的影响,并用恒流充放电、扫描电子显微镜(SEM)和交流阻抗(AC)对添加上述3种导电剂制备得到的电极片进行研究.结果表明,采用该调浆流程能够克服CNTs在使用时出现的团聚问题,CNTs/AB复合物在改善Li_4Ti_5O_(12)电化学性能尤其在容量发挥和倍率性能方面比单一AB和CNTs具有明显优势.CNTs/AB复合物中两者的质量百分比为1:2～1:1时,0.5C时,Li_4Ti_5O_(12)电极的首次放电容量可高达157.0mAh/g,10.0C时,其放电容量可达到128.3mAh/g.与单一导电剂AB和CNTs相比,CNTs与AB复合使用时,由于CNTs的高长径比和良好导电性能使之能够起到"桥梁"作用把部分没有与活性物质充分接触的颗粒状导电剂AB与活性物质连接起来,因此两者的有机结合提高了CNTs/AB与活性材料的接触面积,使电极片能够形成有效的导电网络,有利于Li_4Ti_5O_(12)导电性能的提高.

Carbon nanotubes containing conductive additives to improve the electrochemical performance of Li_4Ti_5O_(12) anode

A practical method of preparation of electrode paste mixture was adopted to evaluated the carbon nanotubes/acetylene black (CNTs/AB) composite,acetylene black (AB) and carbon nanotubes (CNTs) as conductive additives impacting on the electrochemical performance of Li4Ti5O12 electrode.The obtained Li4Ti5O12 electrodes were characterized by constant current charge and discharge tests,scanning electron microscopy (SEM) and AC impedance (AC).The results indicate that the adopted method of preparation of electrod...