title: Porous nanoarchitectures of spinel-type transition metal oxides for electrochemical energy storage systems.
abstract: Transition metal oxides possessing two kinds of metals (denoted as AxB3-xO4, which is generally defined as a spinel structure; A, B = Co, Ni, Zn, Mn, Fe, etc.), with stoichiometric or even non-stoichiometric compositions, have recently attracted great interest in electrochemical energy storage systems (ESSs). The spinel-type transition metal oxides exhibit outstanding electrochemical activity and stability, and thus, they can play a key role in realising cost-effective and environmentally friendly ESSs. Moreover, porous nanoarchitectures can offer a large number of electrochemically active sites and, at the same time, facilitate transport of charge carriers (electrons and ions) during energy storage reactions. In the design of spinel-type transition metal oxides for energy storage applications, therefore, nanostructural engineering is one of the most essential approaches to achieving high electrochemical performance in ESSs. In this perspective, we introduce spinel-type transition metal oxides with various transition metals and present recent research advances in material design of spinel-type transition metal oxides with tunable architectures (shape, porosity, and size) and compositions on the micro- and nano-scale. Furthermore, their technological applications as electrode materials for next-generation ESSs, including metal-air batteries, lithium-ion batteries, and supercapacitors, are discussed.
authors.affiliation: Advanced Batteries Research Center, Korea Electronics Technology Institute (KETI), 68 Yatap-dong, Bundang-gu, Seongnam 463-816, Republic of Korea.
authors.forename: Min-Sik
authors.initials: MS
authors.lastname: Park
authors.affiliation: Institute for Superconducting and Electronic Materials (ISEM), Australian Institute for Innovative Materials (AIIM), University of Wollongong, North Wollongong, NSW 2500, Australia. jhk@uow.edu.au.
authors.forename: Jeonghun
authors.initials: J
authors.lastname: Kim
authors.affiliation: Advanced Batteries Research Center, Korea Electronics Technology Institute (KETI), 68 Yatap-dong, Bundang-gu, Seongnam 463-816, Republic of Korea.
authors.forename: Ki Jae
authors.initials: KJ
authors.lastname: Kim
authors.affiliation: New and Renewable Energy Research Division, Korea Institute of Energy Research, 152 Gajeong-ro, Yuseong-gu, Daejeon 305-343, Republic of Korea. jjong277@kier.re.kr.
authors.forename: Jong-Won
authors.initials: JW
authors.lastname: Lee
authors.affiliation: Institute for Superconducting and Electronic Materials (ISEM), Australian Institute for Innovative Materials (AIIM), University of Wollongong, North Wollongong, NSW 2500, Australia. jhk@uow.edu.au.
authors.forename: Jung Ho
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan and National Institute of Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan. yamauchi.yusuke@nims.go.jp.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Yamauchi