An ultrahigh mass-loading integrated high coulombic efficiency Si–graphite electrode for high-energy-density lithium ion batteries

Abstract

Nowadays, researchers are increasingly interested in silicon-based anode active materials for lithium-ion batteries, which could meet the ever-increasing demand for high energy density owing to their satisfactory theoretical capacity (∼4200 mA h g⁻¹). However, replacing graphite with silicon is still insurmountable due to unsatisfactory coulombic efficiency (ICE), low electrode loading, and insufficient areal capacity. In this study, a silicon–graphite electrode is developed to overcome these limitations, providing excellent experimental data, i.e., a promising ICE of 88%, an ultrahigh areal capacity of 7.4 mA h cm⁻² and an impressive loading level of ∼20 mg cm⁻². Additionally, special characterization, such as stress simulation and friction tests, further verified the stability of the rationally designed electrode. Such satisfactory performance is ascribed to the enhanced conductivity induced by carbon nanotube insertion and boron modification, a reliable volume buffer effect originating from the graphite framework, and ion transport promotion and side reaction prevention induced by lithium-rich binder engineering.