Inhibiting Sn coarsening to enhance the reversibility of conversion reaction in lithiated SnO2 anodes by application of super-elastic NiTi films
By Renzong Hu and Yunpeng Ouyang and Dongchang Chen and Hui Wang and Yu Chen and Min Zhu and Meilin Liu
Published in Acta Materialia
2016
Abstract
The large capacity loss and low initial Coulombic efficiency (ICE) of a conventional SnO2-based anode for Li ion batteries are originated largely from the limited reversibility of the conversion reaction associated with the anode. Often, the reversibility of the lithiation/delithiation of SnO2 (with a high \ICE\ value of ?82%) declines with Sn coarsening in the Sn/Li2O mixture during cycling, leading to gradual capacity decay. Here we demonstrate that the application of super-elastic films of NiTi alloy could accommodate the internal stress and volume change of lithiated nano-SnO2 layer in a tri-layer NiTi/SnO2/NiTi sandwich anode, effectively suppressing Sn coarsening. This unique electrode configuration has helped to retain the high reversibility of the SnO2 layer with reversible capacity more than 800