Improving the Performance of High Capacity Li-Ion Anode Materials by Lithium Titanate Surface Coating

Abstract

Current methods for improving the electrochemical performance of lithium-ion battery electrode materials mostly depend on materials design and synthesis. We propose that the unique electrochemical properties of spinel lithium titanate (Li4Ti5O12, LTO) make it suitable as a protective coating to improve the performance of high capacity anode materials. In this study, tin oxide was coated with LTO to reduce the initial irreversible capacity loss because of solid electrolyte interface (SEI) formation and to improve the reversibility (capacity and rate performance) of tin oxide for Li+ storage. The LTO coating was applied to porous hollow tin oxide particles by a two-step process. Experimental measurements showed that the LTO coating shielded most of the direct contact between tin oxide and the electrolyte and hence the ICL due to SEI formation was reduced to mostly that of LTO, which is much lower than tin oxide. In addition the coated tin oxide also showed notable improvements in material cyclability and rate performance.