Li4Ti5O12-rutile TiO2 nanosheet composite as a high performance anode material for lithium-ion battery

•Rutile TiO2 modifying improves conductivity and Li migration ability of electrode.•Li4Ti5O12-rutile TiO2 shows a high rate capability in a broad voltage window.•Li4Ti5O12-rutile TiO2 exhibits a good cycle stability even at 12 C rates.

Li4Ti5O12 and Li4Ti5O12-rutile TiO2 nanosheet composite were synthesized by a facile solvothermal method with further calcination. The addition of rutile TiO2 does not affect the crystal structure, particle size, morphology of spinel Li4Ti5O12. XRD shows that the molar ratio of Li/Ti has much influence on the chemical composition of the products. TEM indicates that both Li4Ti5O12 and Li4Ti5O12-rutile TiO2 samples are composed of nanoplates with particle size of 50–100 nm. CV and EIS imply that Li4Ti5O12-rutile TiO2 has higher reversible intercalation and deintercalation of Li+, larger lithium-ion diffusion coefficient and smaller charge transfer resistance corresponding to a much higher conductivity than those of Li4Ti5O12 corresponding to the extraction of Li+ ions. Li4Ti5O12-rutile TiO2 material exhibits excellent cycling stability and rate capability in relevant lithium-ion batteries, which can retain a capacity of 120.5 mAh g−1 after 150 cycles at 5 C charge–discharge rate cycled between 1.0 and 2.5 V. This performance is much better than that of pristine Li4Ti5O12 (82.2 mAh g−1), whose capacity fades seriously. Li4Ti5O12-rutile TiO2 also exhibits a good rate performance in a broad voltage window. The capacities of Li4Ti5O12-rutile TiO2 and Li4Ti5O12 charge-discharged at 12 C rates remains at 125.4 and 50.2 mAh g−1 cycled between 0.0 and 2.5 V after 200 cycles, respectively. The enhanced performance of Li4Ti5O12-rutile TiO2 is ascribed to the improved electronic conduction and the reduced polarization resulting from the rutile TiO2 modification together with nanosized structure.