Enhancing the electrochemical performance of silicon anodes for lithium-ion batteries: One-pot solid-state synthesis of Si/Cu/Cu3Si/C electrode

Abstract

To obtain Si anodes with high-performance Li-ion batteries, a nanostructured Si-based composite is synthesized via a facile one-pot solid-state reaction. The Si-based anode composed of Si, Cu, and polyvinylidene fluoride (PVDF) binder is heated at 500 °C under continuous argon flow to obtain a Si/Cu/Cu3Si/C (SCCC) anode. The Cu/Cu3Si phases and carbonized PVDF provide conductive pathways between active Si particles, improving electrical conductivity. In addition, Cu3Si phases form between Si and Cu, anchor metallic Cu in Si particles and help to maintain electronic conductivity and alleviate mechanical stress during cycling. As a result, the SCCC anode shows significantly enhanced electrochemical properties. It delivers 1,773 mAh g−1 after 300 cycles at a current density of 2 A g-1, whereas the Si anode exhibits close to zero capacity. The improvements in electrochemical performance are ascribed to reduced internal resistance and mechanical stress resulting from the Cu/Cu3Si phases and carbonized PVDF binder.