Crystalline SnO2 @ amorphous TiO2 core-shell nanostructures for high-performance lithium ion batteries

Abstract

Tin oxide (SnO2) is an attractive anode in lithium ion batteries (LIBs), but its applications have been significantly hampered by the huge volume change during the electrochemical cycling. In this work we demonstrate a rational design of crystalline SnO2 @ amorphous TiO2 core-shell nanostructures, where the crystalline SnO2 core was synthesized by a hydrothermal method and the amorphous TiO2 shell was deposited by atomic layer deposition. The SnO2@TiO2 nanostructures deliver excellent performances during the electrochemical process, having a high reversible capacity of 1259 mAh g−1 at cycling rate of 80 mA g−1, which is still up to 703 mAh g−1 after 50 cycles. The acceptable rate capacity is also revealed with 412 mAh g−1 at 400 mA g−1. The coulombic efficiency is stable at around 100% regardless of cycling rates and numbers. The electrochemical performances of the SnO2@TiO2 batteries are better than those of the SnO2 ones without TiO2 coating. In the SnO2@TiO2 nanostructures, the amorphous TiO2 shell layer can experience an isotropic stress, having the ability to evidently reduce the volume change, lattice stress and so the risk of fracture during the cycling process, which is responsible for their outstanding behaviors. The strategy provided in our study is expected to be a precious guideline for designing an ideal electrode for energy storage devices.