Nonporous TiO 2 @C Microsphere with a Highly Integrated Structure for High Volumetric Lithium Storage and Enhance Initial Coulombic Efficiency

Abstract To enhance the volumetric energy density and initial coulombic efficiency (ICE) of titanium oxide (TiO₂) as anode electrode material for lithium-ion batteries (LIB), this study employed a surface-confined in-situ inter-growth mechanism to prepare a TiO₂ embedded carbon microsphere composite. The results revealed that the composite exhibited a highly integrated structure of TiO₂ with oxygen vacancies and carbon, along with an exceptionally small specific surface area of 11.52 m²/g. Due to its unique microstructure, the composite demonstrated remarkable lithium storage properties, including a high ICE of 75%, a notable capacity of 426.8 mAh/g after 200 cycles at 0.2 A/g, superior rate performance of 210.1 mAh/g at 5 A/g, and an outstanding cycle life, with a capacity decay rate of only 0.003% per cycle over 2000 cycles. Furthermore, electrochemical kinetic studies further validated the advantages of this microstructure.