Fluoride doping Li4Ti5O12 nanosheets as anode materials for enhanced rate performance of lithium-ion batteries

Fluoride doping Li4Ti5O12 nanosheets (F-LTO NSs) are synthesized using a facile hydrothermal reaction, followed by a calcination treatment. It is found that F atoms can enter the lattice structure of spinel LTO NSs without morphology change. Electrochemical test results shows that the fluoride doping of LTO NSs not only increased the electron conductivity of LTO NSs through trivalent titanium (Ti3+) generation, but also increased the robustness of the structure to repeated lithiation and delithiation. The rate performance of LTO NSs has been evidently improved by F doping. At the highest rate of 5 A g−1 (28.6C), F-LTO NSs still display a capacity retention of 101.4 mA h g−1. F-LTO NSs show superior cycling performance with the high reversible capacity at a current density of 2 A g−1 (11.4C), retaining 84.2% of its initial capacity after 1000 cycles with a capacity retention of 116.8 mA h g−1.