Efficient electrochemical synthesis of Cu3Si/Si hybrids as negative electrode material for lithium-ion battery

Nanoscaling and alloying techniques for silicon-based materials are widely recognized as vital technological approaches to effectively address the challenges associated with volume expansion and poor conductivity in silicon anodes. Developing short process, cost-effective preparation methods and shape controllable silicon-based materials is expected to improve their cyclability. Herein, utilizing the superior electrical conductivity of copper metal and its stable alloy interaction with silicon, the present study introduced a simple synthetic process by incorporating nanoscale Cu ₂O into a SiO ₂ dioxide matrix under a combination of hydrothermal reaction with Cu(NO ₃) ₂ as the copper source and further sintering treatment. Under the conditions of a Cu:Si molar ratio to 3:8 under 850 °C by 2.6 V of constant electrolsyis for 3 h, straight silicon nanowires with a cross-sectional distribution were obtained. The Cu ₃ Si alloy particles were enriched around silicon nanowires. Experimental testing was conducted to evaluate the electrochemical storage capabilities of Cu ₃Si/Si nanowires, resulting in an initial specific capacity of 2630.7 mAh g ^-1 and an initial coulombic efficiency of 88.94%. After 100 charge-discharge cycles, the discharge specific capacity reached 1675.4 mAh g ^-1, with a capacity retention rate of 66.20%. This work demonstrates the effectiveness of constructing a Cu ₃Si conductive network for solving the volume expansion and conductivity problems of Si and the distinctive Cu ₃Si/Si architecture offers an exemplary model for the design of silicon-based composite anodes for advanced lithium-ion batteries.