Controlled synthesis of mesoporous Si/C composites anode via confining carbon coating and Mg gas reduction

The application value of silicon-based anodes has not been fully realized due to the ∼ 300% volume expansion and poor electronic conductivity. In present study, mesoporous Si/C (MP-Si/C) composite with nanosized primary particles of 30–50 nm and pore diameter of 20–40 nm was proposed, which displays superior Li storage properties. Firstly, Polyacrylic acid (PAA) was applied to fulfill in-situ carbon coating and inhibit the particle growth of SiO 2 generated from tetraethyl orthosilicate (TEOS) in stöber reaction. Secondly, Mg gas was introduced to create nano-sized Si with meso -pores and three-dimensional carbon network via the gas-cutting effect. The cycling stability and rate capability were both significantly enhanced with capacity of 671 mAh/g after 400 cycles and 593 mAh/g after 500 cycles at 2 A/g and 4 A/g, respectively, which was highly relevant to the selection of carbon source PAA and its corresponding carbon coating and Mg reduction effect. Moreover, this method bypasses the use of costly nano-silicon, which provides inspiration for the commercialization of silicon-based anodes.