Preparation of an electrochemically-formed spinel lithium manganese oxide and its charge–discharge behaviors

Manganese hydroxides were prepared by a cathodic electrochemical precipitation from a manganese nitrate solution. The grass blade-like precipitate, which is ascribed to manganese hydroxide was 20–80 μm long and 1–5 μm wide and was spread out on a Pt substrate after the electrochemical precipitation. When the electrochemically precipitated manganese hydroxides were kept in an alkali metal hydroxide aqueous solution, such as NaOH, KOH and LiOH, the respective alkali metal ion was incorporated into the precipitate. Fiber-like nano-structured spinel-LiMn2O4 crystals 200 nm in diameter were obtained on a substrate by the calcination of the Li incorporated precipitate at 750 °C without any additives. The electrochemically-formed spinel-LiMn2O4 showed well-shaped CVs, even in higher scan rates. These behaviors are ascribed to the crystal size and shape of the processed spinel-LiMn2O4.