title: Direct Observation of an Anomalous Spinel-to-Layered Phase Transition Mediated by Crystal Water Intercalation.
abstract: The phase transition of layered manganese oxides to spinel phases is a well-known phenomenon in rechargeable batteries and is the main origin of the capacity fading in these materials. This spontaneous phase transition is associated with the intrinsic properties of manganese, such as its size, preferred crystal positions, and reaction characteristics, and it is therefore very difficult to avoid. The introduction of crystal water by an electrochemical process enables the inverse phase transition from spinel to a layered Birnessite structure. Scanning transmission electron microscopy can be used to directly visualize the rearrangement of lattice atoms, the simultaneous insertion of crystal water, the formation of a transient structure at the phase boundary, and layer-by-layer progression of the phase transition from the edge. This research indicates that crystal water intercalation can reverse phase transformation with thermodynamically favored directionality.
authors.affiliation: Graduated School of EEWS and KAIST Institute NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 305-701 (Korea).
authors.forename: Sangryun
authors.initials: S
authors.lastname: Kim
authors.affiliation: Graduated School of EEWS and KAIST Institute NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 305-701 (Korea).
authors.forename: Kwan Woo
authors.initials: KW
authors.lastname: Nam
authors.affiliation: Department of Electronic Chemistry, Tokyo Institute of Technology, 4259 G1-1 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan).
authors.forename: Soyeon
authors.initials: S
authors.lastname: Lee
authors.affiliation: Advanced Batteries Research Center, Korea Electronics Technology Institute (KETI), 25 Saenari-ro, Bundang-gu, Seongnam 463-816 (Republic of Korea).
authors.forename: Woosuk
authors.initials: W
authors.lastname: Cho
authors.affiliation: Graduated School of EEWS and KAIST Institute NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 305-701 (Korea).
authors.forename: Joo-Seong
authors.initials: JS
authors.lastname: Kim
authors.affiliation: Graduated School of EEWS and KAIST Institute NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 305-701 (Korea).
authors.forename: Byung Gon
authors.initials: BG
authors.lastname: Kim
authors.affiliation: School of Materials Science I, Japan Advanced Institute of Science and Technology, 1-1 m1-61 Asahidai, Nomi, Ishikawa 923-1292 (Japan).
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Oshima
authors.affiliation: Material Research Center, Samsung Advanced Institute of Technology, Samsung Electronics Co., LTD, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-803 (Republic of Korea).
authors.forename: Ju-Sik
authors.initials: JS
authors.lastname: Kim
authors.affiliation: Material Research Center, Samsung Advanced Institute of Technology, Samsung Electronics Co., LTD, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-803 (Republic of Korea).
authors.forename: Seok-Gwang
authors.initials: SG
authors.lastname: Doo
authors.affiliation: Material Research Center, Samsung Advanced Institute of Technology, Samsung Electronics Co., LTD, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-803 (Republic of Korea).
authors.forename: Hyuk
authors.initials: H
authors.lastname: Chang
authors.affiliation: Department of Chemistry and Bar-Ilan Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 5290002 (Israel). Doron.Aurbach@biu.ac.il.
authors.forename: Doron
authors.initials: D
authors.lastname: Aurbach
authors.affiliation: Graduated School of EEWS and KAIST Institute NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 305-701 (Korea). jangwookchoi@kaist.ac.kr.
authors.forename: Jang Wook
authors.initials: JW
authors.lastname: Choi
keywords: Birnessite; crystal water; layered cathode materials; phase transitions; spinels