Crystalline and amorphous carbon double-modified silicon anode: Towards large-scale production and superior lithium storage performance

Carbon coating could suppress the volume expansion of silicon toward high-capacity anode materials for lithium-ion batteries. However, whether crystal carbon or amorphous carbon coating always bring new problems to hinder the industrial application. Crystal carbon could not effectively inhibit the volume expansion, and amorphous carbon-coated silicon has low coulombic efficiency. To solve these defects, we prepared the hierarchical structure material (2-BM) of crystalline carbon and amorphous carbon cascade-coated nano-silicon by a simple and easily mass-produced ball milling method. The 2-BM electrode exhibits ~89% initial coulombic efficiency (ICE) and high reversible capacity of 874.5 mAh g−1 after 300 cycles. Various characterizations demonstrated that the superior electrochemical performances of 2-BM mainly benefit from the hierarchical structure, which not only effectively relieves the volume expansion of silicon, but also facilitates the formation of a thin and stable solid electrolyte interface (SEI) film. The easy-to-manufacture hierarchical structure accelerates the industrialization of silicon-carbon materials.