Activation of a MnO2 cathode by water-stimulated Mg2+ insertion for a magnesium ion battery

摘要: Magnesium batteries have been considered to be one of the promising beyond lithium ion technologies due magnesium's abundance, safety, and high volumetric capacity. However, very few materials show reversible performance as a cathode in magnesium systems. We present herein best reported cycling performances MnO2 battery material. that previously poor Mg2+ insertion/deinsertion capacities can greatly improved by synthesizing self-standing nanowires introducing small amount water molecules into electrolyte. Electrochemical elemental analysis results revealed magnitude insertion highly depends on ratio between ions electrolyte highest capacity was observed at 6H2O/Mg2+ demonstrate for first time, nanowire electrode “activated” containing resulting enhanced even with absence molecules. The cycled dry Mg after activation water-containing showed an initial 120 mA h g−1 rate 0.4 C maintained 72% its 100 cycles.