Synthesis of hierarchical porous carbon-TiO2 composites as anode materials for high performance lithium ion batteries

Abstract

Hierarchical porous carbon-TiO2 composites have been successfully synthesized via evaporation-induced self-assembly and in situ crystallization. The titania content and calcination temperature play significant roles in the structures, pore textures (micropore and mesopore) and electrochemical properties. The prepared composites as anode materials for lithium ion batteries show superior discharge capacity, cycling performance and rate capability. The composite of HPCT-600-5 exhibits the highest reversible capacity of 376.9 mAh g−1 after 50 cycles at a rate of 0.1 C, and retains the capacity of 240.5, 180.2 and 117.0 mAh g−1 even at the higher rates of 0.5, 1 and 2 C, respectively (1 C = 350 mA g−1). This outstanding electrochemical performance is attributed to the synergistic effects of hierarchical porous carbon and titania due to the unique structures, such as higher specific surface area and pore volume, fine TiO2 particles, appropriate distribution of hierarchical pore size and optimum content of TiO2. The special structures of the composites can improve the wettability of the electrolyte, provide a large storage space for the Li ion, enhance the initial charge–discharge efficiency and reduce the resistance of the charge transfer and the diffusion of Li ions.