Preparing Carbon-Coated Copper Foil with a Low-Cost and Environmentally Friendly Carbon Slurry to Stabilize Silicon Anode for Lithium-Ion Battery

Introducing a conductive carbon layer between the copper foil current collector and silicon active material effectively mitigates electrode damage and battery capacity loss caused by uneven silicon expansion. In this study, a low-cost, environmentally friendly carbon-coated copper foil (CCF) is designed using zeolitic imidazolate framework 8-derived carbon (ZPC) as the carbon source, polyethylenepyrrolidone (PVP) as the binder, and deionized water as the solvent. The large surface area and porosity of ZPC effectively accommodate the volume expansion of silicon, thereby enhancing the overall performance of the battery. The bare copper foil electrode experiences rapid decay, with a failure occurring after just 75 cycles at 0.5 C. In contrast, the CCF electrode maintains a reversible capacity of 576.8 mAh/g even after 200 cycles. The CCF electrode demonstrates superior specific capacity and cycle stability in both the rate and cycling test. According to the relaxation time distribution (DRT) analysis, the porous carbon layer on the CCF surface ensures excellent electrical contact between silicon and the Cu foil during cycling, facilitates uniform lithium insertion into silicon, prevents uncontrolled growth of the SEI layer, and guarantees stable battery operation. This CCF preparation process provides a promising solution to mitigate the degradation of battery performance caused by silicon expansion.