Tin addition for mechanical and electronic improvement of electrodeposited Si–O–C composite anode for lithium-ion battery

Abstract

The silicon-based composite prepared by electrodeposition exhibits outstanding electrochemical performances for several thousand cycles because the co-deposited oxygen and carbon could act as buffer materials to reduce internal stress during charge-discharge cycling. However, it is not easy to increase the loading amount of active materials due to low structural stability at a high passing charge over 15 C cm−2 for electrodeposition, leading the low areal capacity of Si–O–C composite as an anode. In this study, we propose a new way to enhance the structural stability of silicon-based anode by an electrochemical co-deposition technique using tin as supporting material, namely Sn–Si–O–C composite. The co-deposited tin has a whisker-shaped structure, and it prevents the exfoliation of activated material during electrodeposition. Besides, tin whisker can act as an electron pathway, resulting in improved electrochemical performance including high rate performance. The enhanced electrical conductivity is investigated by electrochemical impedance analysis. The improved electrochemical performance of Sn–Si–O–C composite indicates the high potential as an electrode material for high-performance lithium-ion batteries.