The charge and discharge characteristics of chromium-substituted lithium manganate spinel, LiCr0.1Mn1.9O4, have been studied in organic electrolyte solutions with different compositions. The rate capability and the cycle performance of the oxide cathode depended much on the electrolyte composition. Higher initial capacity was observed in the electrolyte solution showing higher ionic conductivity. Good cycle performance was obtained in LiBF4 solutions with ternary solvent systems containing 1,2-dimethoxyethane (DME). Addition of Li2CO3 to the LiPF6 solution improved the cycleability of the oxide cathode. The electrolyte composition giving lower impedance at the oxide/solution interface showed less capacity degradation during the charge/discharge cycles.