Electrochemical behavior of Li---Mn spinel electrode material in aqueous solution

The electrochemical properties of LiMn2O4 are studied in aqueous solution with various pH values. The performance is similar to that in organic electrolyte. Li1−xMn2O4+xLi++xe− = Mn2O4 in aqueous solution involves two processes: (i) a two-phase reaction at 0.89 V versus saturated calomel electrode (SCE), and (ii) a one-phase reaction at 0.77 versus SCE. LiMn2O4 in LiNO3/HNO3 from pH 2 to 5 is reversible for about 20 cycles. More cycles lead to a great loss in capacity, the reason for which is yet unknown.