Sn@C composite for lithium ion batteries: amorphous vs. crystalline structures

Abstract

Tin has been considered an ideal anode material for lithium ion batteries because of its high theoretical capacity. However, its practical application is limited due to the poor cycling stability, which is induced by the huge volume variation upon lithiation/delithiation. Moreover, amorphous and crystalline structures can significantly influence the electrochemical performance of Sn-based electrode for lithium ion batteries. Herein, the specific capacity, cycling performance, rate capability, and kinetic process of amorphous-Sn@C (am-Sn@C) and crystalline-Sn@C (cr-Sn@C) as anodes for lithium ion batteries have been compared. The am-Sn@C electrode exhibits higher capacity, better cycling stability (711 mAh g−1 after 200 cycles at 0.1 A g−1; 510 mAh g−1 after 500 cycles at 1 A g−1) and rate capability than cr-Sn@C electrode (574 mAh g−1 after 200 cycles at 0.1 A g−1; 156 mAh g−1 after 500 cycles at 1 A g−1) as anode for lithium ion batteries. The enhanced electrochemical performance of the am-Sn@C electrode can be attributed to the enhanced strain regulation to accommodate volume change and defect sites to improve lithium storage capacity. The preparation method can be viewed as a reference for the further development of alloy-based anodes with high capacity and long cycle life for lithium ion batteries.