The Effect of Ball Milling on the Electrochemical Behavior of Silicon Composite Electrode

Abstract

Silicon material possesses the highest theoretic capacity (4200mAh/g, ten times of the capacity of commercialized carbon anode materials) of all known anode materials for lithium ion batteries and thus receives lots of attention to date. Silicon-containing composite electrode for lithium ion batteries was prepared by high-energy ball milling process. The microstructure and morphology of silicon electrode was investigated in detail. The effect of the structure transformation of the electrode by ball milling on the electrochemical behavior was systematically analyzed. Electrode precursors after a mediate ball milling time of 45min is beneficial to get a better cycling performance, due to the well distributed and less destroy of Carboxyl Methyl Cellulose (CMC). Weak lithium insertion into CMC occurs unavoidably in the charging-discharging process of the composite electrodes, which should be the main reason for the sudden disability of electrode. The electrochemical properties can get a dramatic enhancement within voltage window of 0.02-1.5V. Excellent cyclability with high capacity retention above 1800mAh/g after 40 cycles could be gained by controlling the ball-milling time and the voltage windows. It might be a feasible way to obtain satisfactory cyclability for high capacity anode materials.