Conductive Polymers as Positive Electrodes in Rechargeable Aluminum Batteries

Rechargeable batteries based on aluminum are attrac tive alternatives to those based on conventional chemist ries because of the low cost and high charge-storage cap acity of aluminum. Aluminum is the most abundant metal i n the earth’s crust, and its cost is significantly lo wer than that of most other metals used for electrochemical energy storage. The volumetric capacity of aluminum metal is 8.0 Ah cm, which is four times higher than that of lithium. Aluminum is also competitive in terms of gravi metric capacity (3.0 Ah g -1 vs. lithium’s 3.9 Ah g or sodium’s 1.2 Ah g). Aluminum batteries based on aqueous or high-temperature molten salt electrolytes have b e n the subject of extensive research but have faced prohib itive technical barriers (1). An alternative type of rec hargeable aluminum battery is based on room-temperature ionic liquids containing imidazolium salts and aluminum c hloride (2). Electrochemical plating and stripping of aluminum metal in such solutions have been studied in de tail (3-5), forming the basis for the negative electrode in a rechargeable aluminum battery. Active materials fo r the positive electrode have been far less explored.