Cation-Disorder-Assisted Reversible Topotactic Phase Transition between Antifluorite and Rocksalt Toward High-Capacity Lithium-Ion Batteries

• Published in: ACS applied materials & interfaces Vol. 12; no. 39; pp. 43605 - 43613
• Main Authors: Kobayashi, Hiroaki, Tsukasaki, Takashi, Ogasawara, Yoshiyuki, Hibino, Mitsuhiro, Kudo, Tetsuichi, Mizuno, Noritaka, Honma, Itaru, Yamaguchi, Kazuya
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 30.09.2020
• Subjects: Energy, Environmental, and Catalysis Applications; high-capacity cathode; topotactic phase transition; solid-state oxygen redox; cation-disorder; antifluorite; lithium-ion battery
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.0c10768

Multielectron reaction electrode materials using partial oxygen redox can be potentially used as cathodes in lithium-ion batteries, as they offer numerous advantages, including high reversible capacity and energy density and low cost. Here, a reversible three-electron reaction is demonstrated utilizing topotactic phase transition between antifluorite and rocksalt in a cation-disordered antifluorite-type cubic Li6CoO4 cathode. This cubic phase is synthesized by a simple mechanochemical treatment of conventionally prepared tetragonal Li6CoO4. It displays a reversible capacity of 487 mAh g–1, a high value because of a reversible three-electron reaction using Co2+/Co3+, Co3+/Co4+, and O2–/O2 2– redox, occurring without O2 gas evolution. The mechanochemical treatment is assumed to reduce its lattice distortion by cation-disordering and facilitate a reversible topotactic phase transition between antifluorite and rocksalt structures via a dynamic cation pushing mechanism.