Characterization and Optimization of Silicon Nanoparticle Anodes

Lithium-ion batteries with higher energy and power density are required as power sources. Silicon is very attractive as an anode material for lithium-ion batteries because of its high capacity. Silicon anode has problems, which include the expansion and cracking of silicon particles by electrochemical lithiation. In order to overcome this problem, silicon nanoparticle as an anode material is proposed. Since the silicon nanoparticle can be easily oxidized the influence of oxygen content of silicon particle was investigated. The initial coulombic efficiency of lithium extraction/insertion decreased when the oxygen content increased. It was found that adding of metal elements such as Al, Zr, La, Ca during preparing silicon nanoparticles by a thermal plasma method is effective to decrease the formation of silicon oxide. In particular, a cell with an anode formed from Al adding silicon particles exhibited high power density of 2835 W kg(-1) like a capacitor. Conductive agent content gives influence to the performance of the electrode. The choice of a binder is very important to solve the problem of the large capacity fade observed along cycling. Thus, the influences of conductive additive contents and polymer binders of silicon electrodes on the electrochemical performance were investigated. (C) The Electrochemical Society of Japan, All rights reserved.