In-situ mechanochemical synthesis of sub-micro Si/Sn@SiOx-C composite as high-rate anode material for lithium-ion batteries

Micrometer silicon (MSi) particles are prospective anode material for high energy-density lithium-ion batteries. Aiming at the scale-up production and the improvement in rate capability, a novel sub-micro Si/Sn@SiO x -C (SSSC) composite via a facile two-step process of milling and annealing is designed and synthesized. With the structural uniqueness including in-situ introduction of metallic tin (Sn) originated from mechano-reduction of nano tin dioxide (nano-SnO 2 ) with MSi, dual-buffering of inner SiO x matrix and uniform surface carbon layer , SSSC electrodes exhibit impressive rate capability and stable cyclability. The optimum architecture of SSSC-73 ( i.e. weight ratio of precursor MSi-to-SnO 2 is 7:3) delivers stable cycling with 1102 mAh g − 1 (at 0.5 A g − 1 ) over 100 cycles and exceptional rate performance with a high capacity retention of 95% over 500 cycles at 2 A g − 1 . Particularly, this facile and cost-effective preparation of SSSC composites has no by-products, making it competitive in practical application.