Moisture Battery Formed by Direct Contact of Magnesium with Foamed Polyaniline.

The present communication reports a concept battery made by direct contact of magnesium foil with ultralight polyaniline (PANI) foam in the absence of additional electrolyte. Electrical current is allowed to be steadily released from the junction with a specific energy of 646 mWh g(-1) and specific capacity of 1247 mAh g(-1). Additionally, the battery offers an environmentally friendly route of hydrogen production along with discharging. Mechanistic studies indicated that the ubiquitous galvanic corrosion combined with decomposition of adsorbed trace water in the semi-conducting polymer foam enabled the generation of electricity, which overturns the traditional view. The higher moisture level is conducive to the discharge. This work is believed to open up new possibilities for the design of electrochemical batteries.