title: Atomic-Scale Observations of (010) LiFePO4 Surfaces Before and After Chemical Delithiation.
abstract: The ability to view directly the surface structures of battery materials with atomic resolution promises to dramatically improve our understanding of lithium (de)intercalation and related processes. Here we report the use of state-of-the-art scanning transmission electron microscopy techniques to probe the (010) surface of commercially important material LiFePO4 and compare the results with theoretical models. The surface structure is noticeably different depending on whether Li ions are present in the topmost surface layer or not. Li ions are also found to migrate back to surface regions from within the crystal relatively quickly after partial delithiation, demonstrating the facile nature of Li transport in the [010] direction. The results are consistent with phase transformation models involving metastable phase formation and relaxation, providing atomic-level insights into these fundamental processes.
authors.affiliation: Nanostructures Research Laboratory, Japan Fine Ceramics Center , Atsuta, Nagoya 456-8587, Japan.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Kobayashi
authors.affiliation: Nanostructures Research Laboratory, Japan Fine Ceramics Center , Atsuta, Nagoya 456-8587, Japan.
authors.forename: Craig A J
authors.initials: CA
authors.lastname: Fisher
authors.affiliation: Nanostructures Research Laboratory, Japan Fine Ceramics Center , Atsuta, Nagoya 456-8587, Japan.
authors.forename: Takeharu
authors.initials: T
authors.lastname: Kato
authors.affiliation: Office of Society-Academia Collaboration for Innovation, Kyoto University , Uji, Kyoto 611-0011, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Ukyo
authors.affiliation: Nanostructures Research Laboratory, Japan Fine Ceramics Center , Atsuta, Nagoya 456-8587, Japan.
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Hirayama
authors.affiliation: Nanostructures Research Laboratory, Japan Fine Ceramics Center , Atsuta, Nagoya 456-8587, Japan.|Institute of Engineering Innovation, The University of Tokyo , Bunkyo, Tokyo 113-8656, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Ikuhara
keywords: Lithium iron phosphate; delithiation; scanning transmission electron microscopy; single crystal; surface structure