title: "Water-in-salt" electrolyte enables high-voltage aqueous lithium-ion chemistries.
abstract: Lithium-ion batteries raise safety, environmental, and cost concerns, which mostly arise from their nonaqueous electrolytes. The use of aqueous alternatives is limited by their narrow electrochemical stability window (1.23 volts), which sets an intrinsic limit on the practical voltage and energy output. We report a highly concentrated aqueous electrolyte whose window was expanded to ~3.0 volts with the formation of an electrode-electrolyte interphase. A full lithium-ion battery of 2.3 volts using such an aqueous electrolyte was demonstrated to cycle up to 1000 times, with nearly 100% coulombic efficiency at both low (0.15 coulomb) and high (4.5 coulombs) discharge and charge rates.
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD 20740, USA.
authors.forename: Liumin
authors.initials: L
authors.lastname: Suo
authors.affiliation: Electrochemistry Branch, Sensor and Electron Devices Directorate, Power and Energy Division, U.S. Army Research Laboratory, Adelphi, MD 20783, USA.
authors.forename: Oleg
authors.initials: O
authors.lastname: Borodin
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD 20740, USA.
authors.forename: Tao
authors.initials: T
authors.lastname: Gao
authors.affiliation: Electrochemistry Branch, Sensor and Electron Devices Directorate, Power and Energy Division, U.S. Army Research Laboratory, Adelphi, MD 20783, USA.
authors.forename: Marco
authors.initials: M
authors.lastname: Olguin
authors.affiliation: Electrochemistry Branch, Sensor and Electron Devices Directorate, Power and Energy Division, U.S. Army Research Laboratory, Adelphi, MD 20783, USA.
authors.forename: Janet
authors.initials: J
authors.lastname: Ho
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD 20740, USA.
authors.forename: Xiulin
authors.initials: X
authors.lastname: Fan
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD 20740, USA.
authors.forename: Chao
authors.initials: C
authors.lastname: Luo
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD 20740, USA. cswang@umd.edu conrad.k.xu.civ@mail.mil.
authors.forename: Chunsheng
authors.initials: C
authors.lastname: Wang
authors.affiliation: Electrochemistry Branch, Sensor and Electron Devices Directorate, Power and Energy Division, U.S. Army Research Laboratory, Adelphi, MD 20783, USA. cswang@umd.edu conrad.k.xu.civ@mail.mil.
authors.forename: Kang
authors.initials: K
authors.lastname: Xu