title: Stable silicon-ionic liquid interface for next-generation lithium-ion batteries.
abstract: We are currently in the midst of a race to discover and develop new battery materials capable of providing high energy-density at low cost. By combining a high-performance Si electrode architecture with a room temperature ionic liquid electrolyte, here we demonstrate a highly energy-dense lithium-ion cell with an impressively long cycling life, maintaining over 75% capacity after 500 cycles. Such high performance is enabled by a stable half-cell coulombic efficiency of 99.97%, averaged over the first 200 cycles. Equally as significant, our detailed characterization elucidates the previously convoluted mechanisms of the solid-electrolyte interphase on Si electrodes. We provide a theoretical simulation to model the interface and microstructural-compositional analyses that confirm our theoretical predictions and allow us to visualize the precise location and constitution of various interfacial components. This work provides new science related to the interfacial stability of Si-based materials while granting positive exposure to ionic liquid electrochemistry.
authors.affiliation: Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, Colorado 80309, USA.
authors.forename: Daniela
authors.initials: D
authors.lastname: Molina Piper
authors.affiliation: Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, Colorado 80309, USA.
authors.forename: Tyler
authors.initials: T
authors.lastname: Evans
authors.affiliation: Sandia National Laboratories, Albuquerque, New Mexico 87185, USA.
authors.forename: Kevin
authors.initials: K
authors.lastname: Leung
authors.affiliation: Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: Tylan
authors.initials: T
authors.lastname: Watkins
authors.affiliation: Boulder Ionics Corporation, 18300 West Highway 72, Arvada, Colorado 80007, USA.
authors.forename: Jarred
authors.initials: J
authors.lastname: Olson
authors.affiliation: Department of Material Science and Engineering, Seoul National University, Seoul 151-742, Korea.
authors.forename: Seul Cham
authors.initials: SC
authors.lastname: Kim
authors.affiliation: Department of Material Science and Engineering, Seoul National University, Seoul 151-742, Korea.
authors.forename: Sang Sub
authors.initials: SS
authors.lastname: Han
authors.affiliation: Boulder Ionics Corporation, 18300 West Highway 72, Arvada, Colorado 80007, USA.
authors.forename: Vinay
authors.initials: V
authors.lastname: Bhat
authors.affiliation: Department of Material Science and Engineering, Seoul National University, Seoul 151-742, Korea.
authors.forename: Kyu Hwan
authors.initials: KH
authors.lastname: Oh
authors.affiliation: Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Buttry
authors.affiliation: Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, Colorado 80309, USA.
authors.forename: Se-Hee
authors.initials: SH
authors.lastname: Lee