Pulsed Laser Deposited Sns-Snse Composite Thin Film As a New Anode Material for Lithium Storage
In this work, SnS-SnSe composite thin films are synthesized by plused laser deposition. Its first discharge capacity was 1225.8 mAh g-1 and capacity after three cycles maintained about 650 mAh g-1. SnS-SnSe composite thin film firstly reacted with Li during discharge to form Li2SALi2Se and Sn, then Sn reacted with Li to form LixSn alloy. During the charge, LixSn firstly decomposed to form elementary Sn, then Sn catalyzed Li2S and Li2Se to decompose to rebuild SnS-SnSe composite thin film. Li2S and Li2Se produced during discharge can suffer a certain amount of volume change which enhanced the cycle performance. SnS-SnSe composite thin film had more grain boundary than SnS or SnSe thin film which could effectively enhance electrochemical activity and increase capacity.
Fig.1 The first three CVs of SnS-SnSe composite thin film
Fig.2 Galvanostatic charge-discharge curve of SnS-SnSe composite thin film electrodes
Fig.3 Cycling performance of SnS-SnSe, SnS and SnSe thin films with 20 cycles