The effects of three esters incorporated as co-solvents in 1.2 M LiPF6 EC:EMC:DMC (25:5:70 by volume %) electrolyte were studied in Li[Ni1-x-yCoxAly]O-2/Graphite-SiO pouch cells. The esters: methyl propionate (MP), ethyl acetate (EA) and methyl butyrate (MB) were compared in a variety of tests on the cells. Storage tests at 60 degrees C at both 4.2 V and 2.5 V demonstrated that MB and MP outperformed EA and cells containing 20% MP showed the least voltage drop during the 500 h storage period. In long-term cycling tests at 40 degrees C, cells containing up to 20% ester exhibited similar capacity retention compared to cells with only EC:EMC:DMC solvent. Unwanted lithium plating could be suppressed in cells with 20% MP during charging above 2C compared to ester-free cells, which showed the onset of unwanted lithium plating at 1.8C. This improvement is due to the increased Li+ conductivity of electrolytes containing MP. In addition, the use of up to 40% MP did not enhance reactivity between the charged electrode materials and electrolyte at elevated temperatures according to accelerating rate calorimetry measurements. (c) The Author(s) 2017. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited. All rights reserved.