High-performance silicon-carbon anode material via aerosol spray drying and magnesiothermic reduction

We report a high-performance silicon-carbon (Si-C) composite anode material for lithium-ion (Li-ion) batteries via a scalable production route. Porous silica particles as the precursor of Si is obtained from aerosol spray drying of the commercial silica suspension in water. The silica particles are reduced to porous Si via magnesiothermic reduction followed by carbon coating from chemical vapor deposition (CVD). The kinetics of magnesiothermic reduction of silica is systematically studied thus the conversion and the microstructural properties of obtained porous Si can be precisely optimized. The Si-C composite demonstrates excellent specific capacity of 1835 mAh g−1 and outstanding cycle stability. When used as an additive to the graphite anode, the thick electrodes with total areal loading of 4.0 mg cm−2 containing 20 wt% Si-C and 70 wt% graphite achieve remarkable performance: 850 mAh g−1 overall specific capacity and 3.4 mAh cm−2 areal capacity as well as 92% capacity retention after 200 cycles. Full cells composed of commercial lithium iron phosphate cathode and the Si-C-graphite anode under lean electrolyte condition also demonstrate excellent performance.