Here we report the synthesis and electrochemical performance of 40nm near-uniform lithium titanate (Li4Ti5O12) single crystals. The cubic spinel Li4Ti5O12 nanocrystals are transformed without size changes at 400°C from cubic NaCl type (Li0.4H0.6)2TiO3 nanocrystals that are prepared from hydrothermal synthesized α-Li2TiO3. The prepared Li4Ti5O12 nanocrystals show reduced charge-transfer impedance and exhibit favorable performance under high current charging/discharging due to the reduced Li+ ion diffusion path.