title: Symmetric Electrodes for Electrochemical Energy-Storage Devices.
abstract: Increasing environmental problems and energy challenges have so far attracted urgent demand for developing green and efficient energy-storage systems. Among various energy-storage technologies, sodium-ion batteries (SIBs), electrochemical capacitors (ECs) and especially the already commercialized lithium-ion batteries (LIBs) are playing very important roles in the portable electronic devices or the next-generation electric vehicles. Therefore, the research for finding new electrode materials with reduced cost, improved safety, and high-energy density in these energy storage systems has been an important way to satisfy the ever-growing demands. Symmetric electrodes have recently become a research focus because they employ the same active materials as both the cathode and anode in the same energy-storage system, leading to the reduced manufacturing cost and simplified fabrication process. Most importantly, this feature also endows the symmetric energy-storage system with improved safety, longer lifetime, and ability of charging in both directions. In this Progress Report, we provide the comprehensive summary and comment on different symmetric electrodes and focus on the research about the applications of symmetric electrodes in different energy-storage systems, such as the above mentioned SIBs, ECs and LIBs. Further considerations on the possibility of mass production have also been presented.
authors.affiliation: State Key Laboratory of Materials Processing and Die and Mould Technology School of Materials Science and Engineering Huazhong University of Science and Technology Wuhan 430074 P. R. China; Institute for Superconducting and Electronic Materials University of Wollongong Wollongong NSW 2522 Australia.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Institute for Superconducting and Electronic Materials University of Wollongong Wollongong NSW 2522 Australia.
authors.forename: Shi Xue
authors.initials: SX
authors.lastname: Dou
authors.affiliation: Institute for Superconducting and Electronic Materials University of Wollongong Wollongong NSW 2522 Australia.
authors.forename: Hua Kun
authors.initials: HK
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Materials Processing and Die and Mould Technology School of Materials Science and Engineering Huazhong University of Science and Technology Wuhan 430074 P. R. China.
authors.forename: Yunhui
authors.initials: Y
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Materials Processing and Die and Mould Technology School of Materials Science and Engineering Huazhong University of Science and Technology Wuhan 430074 P. R. China.
authors.forename: Xianluo
authors.initials: X
authors.lastname: Hu
keywords: electrochemical energy storage; lithium‐ion batteries; sodium‐ion batteries; supercapacitors; symmetric electrodes