Stepwise carbon coated submicron silicon dioxide anode for long life lithium ion batteries†

Abstract

The preparation of SiO_x materials that exhibit enduring stable cycling performance and high initial coulombic efficiency (ICE) through cost-effective methods remains a substantial hurdle. Herein, a hybrid carbon-coated SiO-20/G@TMA composite was synthesized using an integrated strategy that combines high-energy ball milling and high-temperature carbonization, employing graphene (G) and trimeric acid (TMA) as carbon sources. The three-dimensional crosslinked conductive network, formed by the mechanically flexible graphene and the carbon-rigid TMA, induces the generation of a LiF-rich SEI film. This film reduces interfacial side reactions and improves the ICE to 74.2%. Furthermore, the SiO-20/G@TMA electrode, characterized by a rigid–flexible hybrid structure, demonstrates excellent capacity retention and impressive rate performance over extended cycling periods. The discharge capacity of the SiO-20/G@TMA anode reaches 848.3 mA h g⁻¹ at a current density of 0.5 A g⁻¹, with a reversible capacity of 77% (about 649.1 mA h g⁻¹) maintained after 600 cycles. When paired with a LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) cathode, the SiO-20/G@TMA anode achieves a reversible capacity of 140.0 mA h g⁻¹ at the current density of 0.2 A g⁻¹. After 100 cycles, the capacity retention rate is 85% and the energy density is 474.7 Wh kg⁻¹.