Enhance the electrochemical performance of Li 4 Ti 5 O 12 with Co doping via a facile mechanical activation strategy

Abstract

Co-doped Li 4 Ti 5 O 12 nanosheets are synthesized via a facile hydrothermal method assisted by mechanical activation technology. The as-prepared Co-doped Li 4 Ti 5 O 12 is characterized by X-ray diffraction, scanning electron microscope and transmission electron microscopy. The morphology measurement shows that the Co-doped Li 4 Ti 5 O 12 still maintain the three-dimensional nanosheet structures and good crystallinity after Co doping. As we expected, Co-doped Li 4 Ti 5 O 12 exhibits higher initial discharge specific capacity, improved cycling performance, and impressive rate capability compared with pristine Li 4 Ti 5 O 12 nanosheets. Even under 20 °C charge/discharge rates, the initial discharge capacity of Co-doped Li 4 Ti 5 O 12 is up to 106 mAh g −1 . The electrochemical impedance spectra measurement further displays that the charge-transfer resistance of Co-doped Li 4 Ti 5 O 12 is much lower than that of pristine one after 20 cycles. The improved electrochemical performance of Co-doped Li 4 Ti 5 O 12 is mainly because the Co doping can effectively enlarge the size of the channel by altering the lattice parameter, which can facilitate Li + diffusion and electron transportation.