title: Reactions in the rechargeable lithium-O2 battery with alkyl carbonate electrolytes.
abstract: The nonaqueous rechargeable lithium-O(2) battery containing an alkyl carbonate electrolyte discharges by formation of C(3)H(6)(OCO(2)Li)(2), Li(2)CO(3), HCO(2)Li, CH(3)CO(2)Li, CO(2), and H(2)O at the cathode, due to electrolyte decomposition. Charging involves oxidation of C(3)H(6)(OCO(2)Li)(2), Li(2)CO(3), HCO(2)Li, CH(3)CO(2)Li accompanied by CO(2) and H(2)O evolution. Mechanisms are proposed for the reactions on discharge and charge. The different pathways for discharge and charge are consistent with the widely observed voltage gap in Li-O(2) cells. Oxidation of C(3)H(6)(OCO(2)Li)(2) involves terminal carbonate groups leaving behind the OC(3)H(6)O moiety that reacts to form a thick gel on the Li anode. Li(2)CO(3), HCO(2)Li, CH(3)CO(2)Li, and C(3)H(6)(OCO(2)Li)(2) accumulate in the cathode on cycling correlating with capacity fading and cell failure. The latter is compounded by continuous consumption of the electrolyte on each discharge.
authors.affiliation: School of Chemistry, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9ST, UK.
authors.forename: Stefan A
authors.initials: SA
authors.lastname: Freunberger
authors.forename: Yuhui
authors.initials: Y
authors.lastname: Chen
authors.forename: Zhangquan
authors.initials: Z
authors.lastname: Peng
authors.forename: John M
authors.initials: JM
authors.lastname: Griffin
authors.forename: Laurence J
authors.initials: LJ
authors.lastname: Hardwick
authors.forename: Fanny
authors.initials: F
authors.lastname: Bardé
authors.forename: Petr
authors.initials: P
authors.lastname: Novák
authors.forename: Peter G
authors.initials: PG
authors.lastname: Bruce