The low temperature electrochemical performances of 700 and 350nm Li4Ti5O12 were compared. At high rate, room temperature and at low rate and low temperature (0, −10, −20 and −30°C), the 350nm Li4Ti5O12 showed higher capacity than the 700nm Li4Ti5O12. This difference is proposed to result from the shorter diffusion lengths and higher number of lithium insertion sites in the 350nm Li4Ti5O12 compared to the 700nm Li4Ti5O12. However, at high rate and low temperature, a transition in performance was observed, that is, the 700nm 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.