title: A stable lithium-rich surface structure for lithium-rich layered cathode materials.
abstract: Lithium ion batteries are encountering ever-growing demand for further increases in energy density. Li-rich layered oxides are considered a feasible solution to meet this demand because their specific capacities often surpass 200 mAh g-1due to the additional lithium occupation in the transition metal layers. However, this lithium arrangement, in turn, triggers cation mixing with the transition metals, causing phase transitions during cycling and loss of reversible capacity. Here we report a Li-rich layered surface bearing a consistent framework with the host, in which nickel is regularly arranged between the transition metal layers. This surface structure mitigates unwanted phase transitions, improving the cycling stability. This surface modification enables a reversible capacity of 218.3 mAh g-1at 1C (250 mA g-1) with improved cycle retention (94.1% after 100 cycles). The present surface design can be applied to various battery electrodes that suffer from structural degradations propagating from the surface.
authors.affiliation: Graduate School of Energy, Environment, Water, and Sustainability (EEWS), Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.|KAIST Institute NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.|Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502, Japan.
authors.forename: Sangryun
authors.initials: S
authors.lastname: Kim
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: School of Materials Science I, Japan Advanced Institute of Science and Technology (JAIST), 1-1 M1-61 Asahidai, Nomi 923-1292, Japan.
authors.forename: Xiaobin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: School of Materials Science I, Japan Advanced Institute of Science and Technology (JAIST), 1-1 M1-61 Asahidai, Nomi 923-1292, Japan.
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Oshima
authors.affiliation: Graduate School of Energy, Environment, Water, and Sustainability (EEWS), Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.|KAIST Institute NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Jang Wook
authors.identifier: http://orcid.org/0000-0001-8783-0901
authors.initials: JW
authors.lastname: Choi