Linking particle size to improved electrochemical performance of SiO anodes for Li-ion batteries

We demonstrate a first attempt to understand the particle size-dependence of electrochemical Li storage properties of silicon monoxide (SiO). SiO powder particles of different sizes are obtained by planetary ball milling at 300 rpm for 0-12 h. The 10 h-milled SiO sample exhibits relatively uniform particle morphology with significantly reduced particle size, which induces optimal electrochemical Li storage properties. The specific surface area of the 10 h-milled SiO sample is determined to be approximately 20.1 m(2) g(-1), which is more than 22 times that of pristine SiO (similar to 0.9 m(2) g(-1)). The first discharge and charge capacities of the 10 h-milled SiO sample are 2684 and 2091 mA h g(-1), respectively, at 100 mA g(-1). After 150 cycles, the discharge capacity of the 10 h-milled sample remains at 1159 mA h g(-1), while the discharge capacity is only 777 mA h g(-1) for the pristine SiO sample. The mechanism of the capacity loss upon cycling is also analysed and discussed.