We studied the effect of salt concentration and solvent ratio on the cycling performance of LiMn2O4 cathode and graphite anode in LiPF6–ethylene carbonate (EC)–ethyl methyl carbonate (EMC) electrolytes. The results show that solvent ratio has negligible impact on the performance of both electrodes but does affect the issues of thermal compatibility and ionic conductivity. Salt concentration affects the performance in two reverse ways: LiMn2O4 cathode requires low concentration, while graphite anode requires high concentration. It is observed that, during the first cycle, both electrodes produce irreversible capacity and form a solid electrolyte interface (SEI) film on their surface. From the view point of operation at low temperatures, 1M LiPF6 3:7 EC–EMC is recommended for Li-ion cells.