Density functional theory is used to investigate the reactivity, reduction and effect of electrolyte additives such as fluoroethylene carbonate (FEC), lithium bis(oxalate) borate (LiBOB) and lithium difluoro(oxalato) borate (LiDFOB) in propylene carbonate (PC)-based Li-ion battery electrolytes. The structural, thermodynamical and calculated infra-red vibrational analyses indicate that FEC additives reduce prior to PC, providing stable SEI film formation near the graphite anode. The reduction and reaction mechanisms of LiBOB and LiDFOB influence the SEI film composition at the graphite surface. These additives contribute to stable SEI film formation without degradation of the anode structure by PC co-intercalation. (C) 2014 Elsevier B.V. All rights reserved.