Low temperature performance of nanophase Li_4Ti_5O_(12)

摘要

The low temperature electrochemical performances of 700 and 350 nm Li_4Ti_5O_(12) were compared. At high rate, room temperature and at low rate and low temperature (0, -10, -20 and -30 deg C), the 350 nm Li_4Ti_5O_(12) showed higher capacity than the 700 nm Li_4Ti_5O_(12). This difference is proposed to result from the shorter diffusion lengths and higher number of lithium insertion sites in the 350 nm Li_4Ti_5O_(12) compared to the 700 nm Li_4Ti_5O_(12). However, at high rate and low temperature, a transition in performance was observed, that is, the 700 nm material had higher capacity. At high rate and low temperature, it is proposed that interparticle contact resistance becomes rate limiting owing to the temperature dependence of this property and this accounts for the different behavior at low temperature and high rate.