Synchronous modification to realize micron-SiOx anode with durable and superior electrochemical performance for lithium-ion batteries

Abstract

Silicon-based anodes with high theoretical capacity suffer from huge volume expansion and poor electronic conductivity. Herein, micron-SiOx anode synchronously modified by graphite and melamine (SiOx/G@M) with durable and superior electrochemical performance has been proposed through ball-milling and subsequent hydrothermal process. The good compatibility of melamine with SiOx prompts the generation of a uniform melamine coating on the surface of SiOx particles. Benefiting from the unique structural features, the as-prepared SiOx/G@M demonstrate higher initial Coulombic efficiency (ICE) and better electrochemical performance than SiOx/G. Specifically, a high reversible capacity of 990.4 mA h g−1 can be achieved at 100 mA g−1 after 200 cycles. And the capacity loss per cycle is only 0.016 % even at a high current density of 500 mA g−1 during 2000 cycles. The outstanding lithium-storage performance can be attributed to the significant role of graphite and melamine coating on facilitating rapid transport of both electrons and lithium ions, and plays a buffer role in large volume changes of Si-based anodes as well.