Hierarchical TiO₂/C nanocomposite monoliths with a robust scaffolding architecture, mesopore-macropore network and TiO₂-C heterostructure for high-performance lithium ion batteries

Engineering hierarchical structures of electrode materials is a powerful strategy for optimizing the electrochemical performance of an anode material for lithium-ion batteries (LIBs). Herein, we report the fabrication of hierarchical TiO₂/C nanocomposite monoliths by mediated mineralization and carbonization using bacterial cellulose (BC) as a scaffolding template as well as a carbon source. TiO₂/C has a robust scaffolding architecture, a mesopore-macropore network and TiO₂-C heterostructure. TiO₂/C-500, obtained by calcination at 500 °C in nitrogen, contains an anatase TiO₂-C heterostructure with a specific surface area of 66.5 m² g^-1. When evaluated as an anode material at 0.5 C, TiO₂/C-500 exhibits a high and reversible lithium storage capacity of 188 mA h g^-1, an excellent initial capacity of 283 mA h g^-1, a long cycle life with a 94% coulombic efficiency preserved after 200 cycles, and a very low charge transfer resistance. The superior electrochemical performance of TiO₂/C-500 is attributed to the synergistic effect of high electrical conductivity, anatase TiO₂-C heterostructure, mesopore-macropore network and robust scaffolding architecture. The current material strategy affords a general approach for the design of complex inorganic nanocomposites with structural stability, and tunable and interconnected hierarchical porosity that may lead to the next generation of electrochemical supercapacitors with high energy efficiency and superior power density.