On the beneficial effect of rutile TiO2 to improve electrochemical performance of Li4Ti5O12 at low-potential intercalation

Li 4 Ti 5 O 12 /TiO 2 composite, pure Li 4 Ti 5 O 12 and Li 4 Ti 5 O 12 /Li 2 TiO 3 composite are synthesized through a high temperature solid-state approach by adjusting the molar ratio of Li/Ti precursors. Pure Li 4 Ti 5 O 12 can be obtained when the molar ratio of Li/Ti precursor materials is 0.80, while low and over stoichiometric ratio of Li 4 Ti 5 O 12 would lead to the formation of the second phase of rutile TiO 2 and Li 2 TiO 3 , respectively. The electrochemical performance of the obtained materials as anode materials for Li-ion batteries is tested under potential range of 0.02–2.5 V in Li half-cell. The results show that all the samples exhibit two potential plateaus at ~1.5 V and ~0.75 V at various C-rate. Among the obtained samples, Li 4 Ti 5 O 12 /TiO 2 composite exhibits the best cycling stability and rate capability. The second phase TiO 2 facilitates the diffusion of Li + and significantly enhances the rate capability.