Surface structure and high-rate performance of spinel Li4Ti5O12 coated with N-doped carbon as anode material for lithium-ion batteries

Abstract

We have reported a straightforward strategy to fabricate Li4Ti5O12 composites coated with N-doped carbon layer by using NH3 as N source and sugar as C source, which is a benefit for optimizing carbon layer thickness and tuning atomic ratio of N/C. The composite was synthesized by a conventional solid state reaction with ball milled mixture of TiO2, Li2CO3, and sugar as the precursor, then followed by a high temperature annealing in the atmosphere of Ar and NH3. The choice of titanium source has an impact on the Li4Ti5O12 surface morphology as well as electrochemical properties. N-doped TiO2 can lead to the generation of uniform N-doped C-coating layer, resulting in improved electrochemical performances at high current rate. The N-doped C-coating Li4Ti5O12 obtained by using Anatase TiO2 produces a serrated thin carbon layer, showing the best electrochemical behaviors with the discharge capacity of 100 mAh g−1 at high rate of 24 C and 92.2% of initial capacity after 800 cycles at 12 C, which should be one of the promising anode materials for hybrid electric vehicles.