With the aim of improving the rate capability and the safety of nanocrystalline Li4Ti5O12-based high power lithium ion batteries, two high boiling point nitrile-based electrolytes namely, 3-ethoxypropionitrile (CH3CH2OCH2CH2CN, EPN)/1 M LiTFSI and 3-(2,2,2-trifluoro)ethoxypropionitrile (CF3CH2OCH2CH2CN, FEPN)/1 M LiTFSI, are investigated in this study. Both electrolytes demonstrated superior rate capability to that of EC + DMC-based electrolyte, owing to the fast interfacial charge transfer process of lithium insertion/extraction.