A new ionic liquid-based electrolyte for lithium batteries operating at an elevated temperature of 55 degrees C was prepared by combining N-methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl)imide (PP13TFSI) and lithium bis(fluorosulfonyl)imide (LiFSI). The electrolyte does not contain volatile organic components and is thermally stable (up to 285 degrees C) and ionically conductive (2.6 mS cm(-1) at 55 degrees C). The 0.7m LiFSI-PP13TFSI electrolyte has been shown to work effectively with a graphite anode due to the ability of the FSI anions to create a stable solid electrolyte interface on graphite. A discharge capacity of 340-345 mAh g(-1) was achieved at C/10 rate with a coulombic efficiency of 97-98%. The electrolyte is also compatible with LiCo1/3Mn1/3Ni1/3O2 (NMC) cathode material. At the C/10 rate, we achieved a discharge capacity of 160 mAh g(-1). The coulombic efficiency remains high above 99%. (C) 2012 Elsevier B.V. All rights reserved.