Graphitic Carbon Conformal Coating of Mesoporous TiO₂ Hollow Spheres for High-Performance Lithium Ion Battery Anodes

Abstract

Rational design and controllable synthesis of TiO₂ based materials with unique microstructure, high reactivity, and excellent electrochemical performance for lithium ion batteries are crucially desired. In this paper, we developed a versatile route to synthesize hollow TiO₂/graphitic carbon (H-TiO₂/GC) spheres with superior electrochemical performance. The as-prepared mesoporous H-TiO₂/GC hollow spheres present a high specific surface area (298 m² g^–1), a high pore volume (0.31 cm³ g^–1), a large pore size (∼5 nm), well-defined hollow structure (monodispersed size of 600 nm and inner diameter of ∼400 nm, shell thickness of 100 nm), and small nanocrystals of anatase TiO₂ (∼8 nm) conformably encapsulated in ultrathin graphitic carbon layers. As a result, the H-TiO₂/GC hollow spheres achieve excellent electrochemical reactivity and stability as an anode material for lithium ion batteries. A high specific capacity of 137 mAh g^–1 can be achieved up to 1000 cycles at a current density of 1 A g^–1 (5 C). We believe that the mesoporous H-TiO₂/GC hollow spheres are expected to be applied as a high-performance electrode material for next generation lithium ion batteries