Constructing flexible carbon-graphite network for enhancing durability of silicon anodes in Li-ion battery

Abstract

Silicon-based materials still face critical issues including large volume expansion and poor electrical conductivity during the charging and discharging process. Despite the carbon coating strategy can improve performance, the practical operation of silicon-carbon anodes still suffers from undesirable cycling performance. Herein, we propose a novel method to construct Si/SiOx@G@C microparticles, where the Si/SiOx core is coated by conducive and flexible amorphous carbon networks and graphite shells. The Si/SiOx@G@C demonstrated a high discharge capacity of 821 mA h g−1 and an initial Coulombe efficiency of 82.5 % under the current density of 0.1A/g. At a current density of 1.0 A/g, the Si/SiOx@G@C electrodes delivered a high rechargeable capacity retention of 75.1 % and only 117 % volume expansion over 1,000 charge–discharge cycles. The demonstration of silicon-based batteries with a long cycle life is an important step towards the development of this field beyond Li-ion technology.