title: The water catalysis at oxygen cathodes of lithium-oxygen cells.
abstract: Lithium-oxygen cells have attracted extensive interests due to their high theoretical energy densities. The main challenges are the low round-trip efficiency and cycling instability over long time. However, even in the state-of-the-art lithium-oxygen cells the charge potentials are as high as 3.5 V that are higher by 0.70 V than the discharge potentials. Here we report a reaction mechanism at an oxygen cathode, ruthenium and manganese dioxide nanoparticles supported on carbon black Super P by applying a trace amount of water in electrolytes to catalyse the cathode reactions of lithium-oxygen cells during discharge and charge. This can significantly reduce the charge overpotential to 0.21 V, and results in a small discharge/charge potential gap of 0.32 V and superior cycling stability of 200 cycles. The overall reaction scheme will alleviate side reactions involving carbon and electrolytes, and shed light on the construction of practical, rechargeable lithium-oxygen cells.
authors.affiliation: 1] Energy Interface Technology Group, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1, Umezono, Tsukuba 305-8568, Japan [2] Department of Chemical System Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Fujun
authors.initials: F
authors.lastname: Li
authors.affiliation: Energy Interface Technology Group, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1, Umezono, Tsukuba 305-8568, Japan.
authors.forename: Shichao
authors.initials: S
authors.lastname: Wu
authors.affiliation: Energy Interface Technology Group, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1, Umezono, Tsukuba 305-8568, Japan.
authors.forename: De
authors.initials: D
authors.lastname: Li
authors.affiliation: Energy Interface Technology Group, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1, Umezono, Tsukuba 305-8568, Japan.
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
authors.affiliation: National Laboratory of Solid State Microstructures &College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China.
authors.forename: Ping
authors.initials: P
authors.lastname: He
authors.affiliation: Department of Chemical System Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Atsuo
authors.initials: A
authors.lastname: Yamada
authors.affiliation: 1] Energy Interface Technology Group, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1, Umezono, Tsukuba 305-8568, Japan [2] Department of Chemical System Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan [3] National Laboratory of Solid State Microstructures &College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China.
authors.forename: Haoshen
authors.initials: H
authors.lastname: Zhou