Cyclic voltammetry (CV) of LiCr0.15Mn1.85O4, synthesized by rapid glycine-nitrate method (GNM), was performed in a saturated aqueous LiNO3 (∼9M) solution. At rather high polarization rate of 10mVs−1 two well separated characteristic pairs of redox peaks can be clearly observed, which is not entirely the case for LiMn2O4 synthesized in the same way. At a reduced scan rate of 1mVs−1, the shape and position of redox peaks evidence that deintercalation/intercalation of Li+ ion is highly reversible and much faster than in the case of organic electrolytes. Faster “CV response” of LiCr0.15Mn1.85O4 is in correlation with higher capacity retention (93%) in comparison to LiMn2O4 (88%), registered after 50charging/discharging cycles in organic electrolyte solution (1M LiClO4 in propylene carbonate).