Amorphous manganese oxyiodides exhibiting high lithium intercalation capacity at higher current density

The reduction of sodium permanganate with lithium iodide in acetonitrile medium to obtain amorphous manganese oxyiodides has been investigated systematically. The electrochemical performance of the oxyiodides depends on the composition, which in turn is controlled by the permanganate to lithium iodide ratio in the reaction mixture. Optimized compositions and electrode- making process give a capacity of 335, 275, and 220 mAh/ g, respectively, at a current density of 0.05, 0.5, and 1 mA/cm(2) in the range 4.3-1.5 V. The oxyiodide exhibits the highest reversible capacity of all known manganese oxides, with 100% capacity retention. (C) 1999 The Electrochemical Society. S1099- 0062( 98) 07- 084- 9. All rights reserved.