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

Li 4 Ti 5 O 12 and Li 4 Ti 5 O 12 -rutile TiO 2 nanosheet composite were synthesized by a facile solvothermal method with further calcination. The addition of rutile TiO 2 does not affect the crystal structure, particle size, morphology of spinel Li 4 Ti 5 O 12 . XRD shows that the molar ratio of Li/Ti has much influence on the chemical composition of the products. TEM indicates that both Li 4 Ti 5 O 12 and Li 4 Ti 5 O 12 -rutile TiO 2 samples are composed of nanoplates with particle size of 50–100 nm. CV and EIS imply that Li 4 Ti 5 O 12 -rutile TiO 2 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 Li 4 Ti 5 O 12 corresponding to the extraction of Li + ions. Li 4 Ti 5 O 12 -rutile TiO 2 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 Li 4 Ti 5 O 12 (82.2 mAh g −1 ), whose capacity fades seriously. Li 4 Ti 5 O 12 -rutile TiO 2 also exhibits a good rate performance in a broad voltage window. The capacities of Li 4 Ti 5 O 12 -rutile TiO 2 and Li 4 Ti 5 O 12 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 Li 4 Ti 5 O 12 -rutile TiO 2 is ascribed to the improved electronic conduction and the reduced polarization resulting from the rutile TiO 2 modification together with nanosized structure. [ABSTRACT FROM AUTHOR]