Synthesis and electrochemical properties of Li5+xFe1–xMnxO4 with an antifluorite-type structure as a lithium battery cathode

A new antifluorite-structured Li5+xFe1–xMnxO4 was synthesized by conventional solid-state reaction and the lithium (de-)intercalation properties were characterized from electrochemical measurements. A single phase with a Li6MnO4-type structure was obtained for the x ≥ 0.6 compositions. The first discharge capacity of a Li5.6Fe0.4Mn0.6O4 (x = 0.6) electrode treated by ball milling was 450 mAh/g. The reversible reaction continued to proceed with ca. 200 mAh/g after subsequent cycles. A new iron–manganese system with an antifluorite structure could be a potential candidate as a high-capacity cathode material.