title: In Situ Chemical Synthesis of Lithium Fluoride/Metal Nanocomposite for High Capacity Prelithiation of Cathodes.
abstract: The initial lithium loss during the formation stage is a critical issue that significantly reduces the specific capacity and energy density of current rechargeable lithium-ion batteries (LIBs). An effective strategy to solve this problem is using electrode prelithiation additives that can work as a secondary lithium source and compensate the initial lithium loss. Herein we show that nanocomposites of lithium fluoride and metal (e.g., LiF/Co and LiF/Fe) can be efficient cathode prelithiation materials. The thorough mixing of ultrafine lithium fluoride and metal particles (∼5 nm) allows lithium to be easily extracted from the nanocomposites via an inverse conversion reaction. The LiF/Co nanocomposite exhibits an open circuit voltage (OCV, 1.5 V) with good compatibility with that of existing cathode materials and delivers a high first-cycle "donor" lithium-ion capacity (516 mA h g(-1)). When used as an additive to a LiFePO4 cathode, the LiF/Co nanocomposite provides high lithium compensation efficiency. Importantly, the as-formed LiF/metal nanocomposites possess high stability and good compatibility with the regular solvent, binder, and existing battery processing conditions, in contrast with the anode prelithiation materials that usually suffer from issues of high chemical reactivity and instability. The facile synthesis route, high stability in ambient and battery processing conditions, and high "donor" lithium-ion capacity make the LiF/metal nanocomposites ideal cathode prelithiation materials for LIBs.
authors.affiliation: Department of Materials Science and Engineering, Stanford University , Stanford, California 94305, United States.
authors.forename: Yongming
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Department of Materials Science and Engineering, Stanford University , Stanford, California 94305, United States.
authors.forename: Hyun-Wook
authors.initials: HW
authors.lastname: Lee
authors.affiliation: Department of Materials Science and Engineering, Stanford University , Stanford, California 94305, United States.
authors.forename: Guangyuan
authors.initials: G
authors.lastname: Zheng
authors.affiliation: Department of Materials Science and Engineering, Stanford University , Stanford, California 94305, United States.
authors.forename: Zhi Wei
authors.initials: ZW
authors.lastname: Seh
authors.affiliation: Department of Materials Science and Engineering, Stanford University , Stanford, California 94305, United States.
authors.forename: Jie
authors.initials: J
authors.lastname: Sun
authors.affiliation: Department of Materials Science and Engineering, Stanford University , Stanford, California 94305, United States.
authors.forename: Yanbin
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Materials Science and Engineering, Stanford University , Stanford, California 94305, United States.|Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States.
authors.forename: Yi
authors.initials: Y
authors.lastname: Cui
keywords: LiF/metal nanocomposite; cathode prelithiation; conversion reaction; high capacity