Pomegranate-like C@TiO₂ mesoporous honeycomb spheres for high performance lithium ion batteries

Pomegranate-like C@TiO₂ mesoporous honeycomb spheres have been synthesized through two simple steps: formation of TiO₂ mesoporous honeycomb spheres and the coating of polypyrrole followed by carbonization. TiO₂ mesoporous honeycomb spheres are of large specific surface area of 153 m² g^-1 and contain abundant mesopores, which leads to high electrochemical activity and good kinetic performance of TiO₂. A layer of amorphous carbon shell with the thickness of 30-40 nm tightly encapsulates a TiO₂ mesoporous honeycomb sphere, forming a novel pomegranate-like small sphere, which significantly improves electronic conductivity and structural stability of TiO₂. Benefiting from the unique pomegranate-like structure, C@TiO₂ mesoporous honeycomb spheres exhibit high specific capacity, stable long-term cycling performance and good rate capability as an anode material for lithium ion batteries (LIBs). After 500 cycles at 1 C, the discharge capacity still reaches 184 mAh g^-1. The electrochemical performance is superior to pure TiO₂ mesoporous honeycomb spheres and most of the reported high-performance TiO₂-based composites. This work provides a new high-performance TiO₂-carbon-based composite material for LIBs as well as a new valuable research strategy.