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

The preparation of SiOx 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 LiNi0.8Co0.1Mn0.1O2 (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.