Enhanced rate performance of nanosized Li4Ti5O12/graphene composites as anode material by a solid state-assembly method

Abstract

Nanosized Li4Ti5O12/graphene materials have been successfully synthesized by a solid state-assembly method. As the anode materials for lithium ion batteries, nanosized Li4Ti5O12/graphene exhibits higher specific capacity, much improved rate capability, and better cycle stability than the pure Li4Ti5O12. In the potential range of 1.0-2.0V at room temperature, Li4Ti5O12/graphene with weight ratio of LTO:GO to 1000:5 shows discharge capacities of more than 144 and 96.2mAhg−1 after 100 cycles at 1C and 3C charge-discharge rates, while the correspond discharge capacities of pure Li4Ti5O12 are only 108 and 75.4mAhg−1, respectively. The resulting Li4Ti5O15/graphene (1000:5) sample demonstrates remarkable rate capability in that it delivers a reversible capacity of 53.4mAhg−1 in the 1000th cycle at 10C charge-discharge rate, about 240% that of pristine Li4Ti5O12 particles (22.2mAhg−1). The low charge-transfer resistance and large lithium ion diffusion coefficients confirmed that Li4Ti5O12/graphene materials possessed better electronic conductivity and lithium ion mobility. The present work demonstrates that Li4Ti5O12/graphene composite is a promising anode material for high-rate and long life lithium ion batteries and this simple preparation method makes its production on a large scale.