Scalable synthesis of carbon stabilized SiO/graphite sheets composite as anode for high-performance Li ion batteries

Abstract

Mixing Si-based materials with graphite has attracted attention as a feasible alternative anode for practical application in high-energy Li-ion batteries. In this study, amorphous carbon coated SiO/graphite composites (SGCs) are fabricated through in situ polymerization of aniline and followed by annealing treatment, which is simple and scalable. The in situ generated polyaniline serves as a "glue" to stabilize the SiO particles and graphite sheets, thus constructing well-distributed and stable structure. After annealing, the polyaniline-derived carbon layer and graphite could synergistically buffer the volume change of SiO, and form a conductive network. The effect of the weight ratio of SiO and graphite on the overall electrochemical performance is also studied. As a result, the optimized SGC-5 anode (weight ratio: SiO/graphite = 1/5) exhibits the best electrochemical performance, such as a reversible capacity over 540 mA h g-1 at 0.2C, long-term cycling stability with a capacity of 440 mA h g-1 at 0.8C after 500 cycles, and good rate capability. Additionally, the structural change and fading mechanism of these electrodes during cycling are also investigated.