Enhanced high-rate performance of Br-doping Li4Ti5O12 microspheres as anode materials for lithium-ion batteries

Abstract Br-doping Li4Ti5O12 microspheres (LTOS) with micro-nano hierarchical structure are synthesized using cetyltrimethylammonium hydroxide-assisted hydrothermal and further calcination. The structure and morphology of the obtained Br-doping LTOS were characterized by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. It is found that the spherical morphology and spinel-type microstructure of LTOS do not change after appropriate Br doping, but the relative content of Ti3+ increases, which are beneficial for the fast transmission of electronics and ions. Therefore, the rate performances of LTOS are evidently improved after Br doping. Among the doped samples, 0.2Br-LTOS delivers the superior rate performance and cyclic ability. Their specific capacities at 1C, 5C, 10C, 20C, 30C and 40C are 133, 127, 121, 114, 109 and 105 mAh·g−1, respectively. Even at 50C and 60C, their specific capacities are still as high as 101 and 96 mAh·g−1, respectively. Moreover, their capacity retention ratio is about 87.8% after 1000 cycles at 10C, which is higher than 76.5% of pure LTOS.