title: Asymmetric Supercapacitors Using 3D Nanoporous Carbon and Cobalt Oxide Electrodes Synthesized from a Single Metal-Organic Framework.
abstract: Nanoporous carbon and nanoporous cobalt oxide (Co3O4) materials have been selectively prepared from a single metal-organic framework (MOF) (zeolitic imidazolate framework, ZIF-67) by optimizing the annealing conditions. The resulting ZIF-derived carbon possesses highly graphitic walls and a high specific surface area of 350 m(2)·g(-1), while the resulting ZIF-derived nanoporous Co3O4 possesses a high specific surface area of 148 m(2)·g(-1) with much less carbon content (1.7 at%). When nanoporous carbon and nanoporous Co3O4 were tested as electrode materials for supercapacitor application, they showed high capacitance values (272 and 504 F·g(-1), respectively, at a scan rate of 5 mV·s(-1)). To further demonstrate the advantages of our ZIF-derived nanoporous materials, symmetric (SSCs) and asymmetric supercapacitors (ASCs) were also fabricated using nanoporous carbon and nanoporous Co3O4 electrodes. Improved capacitance performance was successfully realized for the ASC (Co3O4//carbon), better than those of the SSCs based on nanoporous carbon and nanoporous Co3O4 materials (i.e., carbon//carbon and Co3O4//Co3O4). The developed ASC with an optimal mass loading can be operated within a wide potential window of 0.0-1.6 V, which leads to a high specific energy of 36 W·h·kg(-1). More interestingly, this ASC also exhibits excellent rate capability (with the highest specific power of 8000 W·kg(-1) at a specific energy of 15 W·h·kg(-1)) combined with long-term stability up to 2000 cycles.
authors.affiliation: †World Premier International (WPI) Research Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
authors.forename: Rahul R
authors.initials: RR
authors.lastname: Salunkhe
authors.affiliation: †World Premier International (WPI) Research Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.|‡Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan.
authors.forename: Jing
authors.initials: J
authors.lastname: Tang
authors.affiliation: †World Premier International (WPI) Research Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.|§Department of Applied Chemistry, Graduate School of Engineering, Kyushu Institute of Technology, 1-1 Sensui-Cho, Tobata, Kitakyushu, Fukuoka 804-8550, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Kamachi
authors.affiliation: §Department of Applied Chemistry, Graduate School of Engineering, Kyushu Institute of Technology, 1-1 Sensui-Cho, Tobata, Kitakyushu, Fukuoka 804-8550, Japan.
authors.forename: Teruyuki
authors.initials: T
authors.lastname: Nakato
authors.affiliation: ∥Institute for Superconducting and Electronic Materials, University of Wollongong, North Wollongong, New South Wales 2500, Australia.
authors.forename: Jung Ho
authors.initials: JH
authors.lastname: Kim
authors.affiliation: †World Premier International (WPI) Research Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.|‡Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Yamauchi
keywords: carbon; cobalt oxide; coordination polymers; metal−organic frameworks; nanoporous materials; supercapacitors