title: Origin of additional capacities in metal oxide lithium-ion battery electrodes.
abstract: Metal fluorides/oxides (MF(x)/M(x)O(y)) are promising electrodes for lithium-ion batteries that operate through conversion reactions. These reactions are associated with much higher energy densities than intercalation reactions. The fluorides/oxides also exhibit additional reversible capacity beyond their theoretical capacity through mechanisms that are still poorly understood, in part owing to the difficulty in characterizing structure at the nanoscale, particularly at buried interfaces. This study employs high-resolution multinuclear/multidimensional solid-state NMR techniques, with in situ synchrotron-based techniques, to study the prototype conversion material RuO2. The experiments, together with theoretical calculations, show that a major contribution to the extra capacity in this system is due to the generation of LiOH and its subsequent reversible reaction with Li to form Li2O and LiH. The research demonstrates a protocol for studying the structure and spatial proximities of nanostructures formed in this system, including the amorphous solid electrolyte interphase that grows on battery electrodes.
authors.affiliation: Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK.
authors.forename: Yan-Yan
authors.initials: YY
authors.lastname: Hu
authors.forename: Zigeng
authors.initials: Z
authors.lastname: Liu
authors.forename: Kyung-Wan
authors.initials: KW
authors.lastname: Nam
authors.forename: Olaf J
authors.initials: OJ
authors.lastname: Borkiewicz
authors.forename: Jun
authors.initials: J
authors.lastname: Cheng
authors.forename: Xiao
authors.initials: X
authors.lastname: Hua
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Dunstan
authors.forename: Xiqian
authors.initials: X
authors.lastname: Yu
authors.forename: Kamila M
authors.initials: KM
authors.lastname: Wiaderek
authors.forename: Lin-Shu
authors.initials: LS
authors.lastname: Du
authors.forename: Karena W
authors.initials: KW
authors.lastname: Chapman
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Chupas
authors.forename: Xiao-Qing
authors.initials: XQ
authors.lastname: Yang
authors.forename: Clare P
authors.initials: CP
authors.lastname: Grey