The novel electrolyte additive lithium dimethyl phosphate (LiDMP) has been synthesized and characterized. Incorporation of LiDMP (0.1% wt) into LiPF6 in ethylene carbonate (EC) / ethyl methyl carbonate (EMC) (3:7 wt) results in improved rate performance and reduced impedance for graphite / LiNi1/3Mn1/3Co1/3O2 cells. Ex-situ surface analysis of the electrodes suggests that incorporation of LiDMP results in a modification of the solid electrolyte interphase (SEI) on the anode. A decrease in the concentration of lithium alkyl carbonates and an increase in the concentration of lithium fluoro phosphates are observed. The change in the anode SEI structure is responsible for the increased rate performance and decreased cell impedance. (C) The Author(s) 2016. Published by ECS. All rights reserved.