title: Rechargeable Metal-Air Proton-Exchange Membrane Batteries for Renewable Energy Storage.
abstract: Rechargeable proton-exchange membrane batteries that employ organic chemical hydrides as hydrogen-storage media have the potential to serve as next-generation power sources; however, significant challenges remain regarding the improvement of the reversible hydrogen-storage capacity. Here, we address this challenge through the use of metal-ion redox couples as energy carriers for battery operation. Carbon, with a suitable degree of crystallinity and surface oxygenation, was used as an effective anode material for the metal redox reactions. A Sn0.9In0.1P2O7-based electrolyte membrane allowed no crossover of vanadium ions through the membrane. The V4+/V3+, V3+/V2+, and Sn4+/Sn2+redox reactions took place at a more positive potential than that for hydrogen reduction, so that undesired hydrogen production could be avoided. The resulting electrical capacity reached 306 and 258 mAh g-1for VOSO4and SnSO4, respectively, and remained at 76 and 91 % of their respective initial values after 50 cycles.
authors.affiliation: Graduate School of Environmental Studies Nagoya University Nagoya 464-8601 Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nagao
authors.affiliation: Graduate School of Environmental Studies Nagoya University Nagoya 464-8601 Japan.
authors.forename: Kazuyo
authors.initials: K
authors.lastname: Kobayashi
authors.affiliation: Institute of Materials and Systems for Sustainability Nagoya University Nagoya 464-8601 Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Yamamoto
authors.affiliation: Research and Development Department Asahi Carbon Co., Ltd. Niigata 950-0883 Japan.
authors.forename: Togo
authors.initials: T
authors.lastname: Yamaguchi
authors.affiliation: Engine Component Department Isuzu Motors Limited Kanagawa 252-0881 Japan.
authors.forename: Akihide
authors.initials: A
authors.lastname: Oogushi
authors.affiliation: Graduate School of Environmental Studies Nagoya University Nagoya 464-8601 Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Hibino
keywords: batteries; energy storage; fuel cells; proton-exchange membranes; redox chemistry