title: Direct observation of a metastable crystal phase of Li(x)FePO4 under electrochemical phase transition.
abstract: The phase transition between LiFePO4 and FePO4 during nonequilibrium battery operation was tracked in real time using time-resolved X-ray diffraction. In conjunction with increasing current density, a metastable crystal phase appears in addition to the thermodynamically stable LiFePO4 and FePO4 phases. The metastable phase gradually diminishes under open-circuit conditions following electrochemical cycling. We propose a phase transition path that passes through the metastable phase and posit the new phase's role in decreasing the nucleation energy, accounting for the excellent rate capability of LiFePO4. This study is the first to report the measurement of a metastable crystal phase during the electrochemical phase transition of LixFePO4.
authors.affiliation: Graduate School of Human and Environmental Studies, Kyoto University, Kyoto 606-8501 Japan. orikasa.yuuki.2a@kyoto-u.ac.jp
authors.forename: Yuki
authors.initials: Y
authors.lastname: Orikasa
authors.forename: Takehiro
authors.initials: T
authors.lastname: Maeda
authors.forename: Yukinori
authors.initials: Y
authors.lastname: Koyama
authors.forename: Haruno
authors.initials: H
authors.lastname: Murayama
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Fukuda
authors.forename: Hajime
authors.initials: H
authors.lastname: Tanida
authors.forename: Hajime
authors.initials: H
authors.lastname: Arai
authors.forename: Eiichiro
authors.initials: E
authors.lastname: Matsubara
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Uchimoto
authors.forename: Zempachi
authors.initials: Z
authors.lastname: Ogumi