Improved electrochemical performance of Si/C material based on the interface stability

Silicon anode is a promising candidate for the next generation electrodes for lithium ion batteries. However, the poor cycle performance of silicon caused by large volume expansion of silicon hinders the practical application of silicon anode. The large volume change results in the reformed solid electrolyte interface layer and the electrode/electrolyte interface is unstable. In this work, the native silica and N-doped carbon layer improve the stability of active particles/electrolyte interface and accommodate volume change so as to enhance the electrochemical performance of silicon-based anode material. The temperature has an effect on the growth of the oxide layer and electrochemical performance of electrode material. Superficial silica content on silicon particles increases as the temperature rises, and the cycle properties are improved as well. The sample presents the proper thickness of the silica layer and the composition of the carbon layer at 800 °C. Electrochemical tests show the sample delivers a capacity of 961.9 mAh g⁻¹ at 100 mA g⁻¹, with initial coulombic efficiency of 84.5%. Reversible specific capacity of 775.7 mAh g⁻¹ is obtained at 200 mA g⁻¹ after 50 cycles, with capacity retention of 86.1%. It also exhibits good cycling performance with a reversible capacity of 484.6 mAh g⁻¹ at 1 A g⁻¹ after 200 cycles. - Highlights: • Si-based material with silica and carbon coating layer is synthesized successfully. • The influence of temperature on property of material is investigated. • The silica and carbon layer improve the particle/electrolyte interface stability.