Defective mesoporous Li_4Ti_5O_(12-y): An advanced anode material with anomalous capacity and cycling stability at a high rate of 20 C

摘要

How to obtain an excellent capacity and cycling stability of electrodes that work at high rates is now challenging the development of lithium-ion batteries. Herein, we initiate a facile solvothermal method to prepare defective mesoporous Li_4Ti_5O_(12- y) as an anode material with an improved high-rate performance for lithium-ion batteries. The high-rate performance for the resultant anode is represented by a discharge capacity of 139 mAh g~(-1) at a high rate of 20 C with a capacity retention of 91.4% over 300 cycles. Different from the strategies popularly used in literature, the current approach does not rely on any aids from conductive layers or foreign dopants, but takes advantages of the unique features of a defective mesoporous structure with oxygen vacancies and Ti~(3+)-O_2-Ti~(4+) pairs. These features enable an improved intrinsic electronic conductivity, which leads to a high-rate performance and cycling stability superior to the stoichiometric mesoporous counterpart when annealing in air. The defective mesoporous Li_4Ti_5O_(12-y) is therefore demonstrated to be a promising advanced anode material for high-rate lithium-ion batteries.