Piezoelectric Composite of BaTiO3-coated SnO2 Microsphere: Li-ion Battery Anode with Enhanced Electrochemical Performance Based on Accelerated Li+ Mobility

Abstract In this study, a BaTiO3-coated SnO2 microsphere composite (SnO2@BaTiO3) with high porosity was prepared via a solvothermal process and solution coating for application as an anode for high-performance Li-ion batteries. BaTiO3 in the as-formed SnO2@BaTiO3 composite generated locally polarized piezoelectric fields under the mechanical stress generated by the volume expansion of SnO2 during the lithiation process. The synergistic effect of the local piezoelectric potential and high porosity of the SnO2@BaTiO3 composite electrode improved its Li+ mobility (DLi+: 3.47 × 10-7 cm2s-1) as compared to that of the SnO2 microsphere (DLi+: 6.65 × 10-8 cm2s-1). The improved Li+ mobility of the SnO2@BaTiO3 composite improved its electrochemical performance as the anode for Li-ion batteries. The composite anode exhibited much better rate performance (559.4 mAh g-1 at 2 A g-1) and cycle stability (571.5 mAh g-1 after 100 cycles at 0.1 A g-1) than the control anodes (SnO2 (324.0 mAh g-1 at 2 A g-1, 58.9 mAh g-1 after 100 cycles at 0.1 A g-1) and BaTiO3 (18.4 mAh g-1 at 2 A g-1, 15.3 mAh g-1 after 100 cycles at 0.1 A g-1).