title: Monolayer Nickel Cobalt Hydroxyl Carbonate for High Performance All-Solid-State Asymmetric Supercapacitors.
abstract: The emergence of atomically thick nanolayer materials, which feature a short ion diffusion channel and provide more exposed atoms in the electrochemical reactions, offers a promising occasion to optimize the performance of supercapacitors on the atomic level. In this work, a novel monolayer Ni-Co hydroxyl carbonate with an average thickness of 1.07 nm is synthesized via an ordinary one-pot hydrothermal route for the first time. This unique monolayer structure can efficiently rise up the exposed electroactive sites and facilitate the surface dependent electrochemical reaction processes, and thus results in outstanding specific capacitance of 2266 F g(-1). Based on this material, an all-solid-state asymmetric supercapacitor is developed adopting alkaline PVA (poly(vinyl alcohol)) gel (PVA/KOH) as electrolyte, which performs remarkable cycling stability (no capacitance fade after 19 000 cycles) together with promising energy density of 50 Wh kg(-1) (202 μWh cm(-2)) and high power density of 8.69 kW kg(-1) (35.1 mW cm(-2)). This as-assembled all-solid-state asymmetric supercapacitor (AASC) holds great potential in the field of portable energy storage devices.
authors.affiliation: Key Laboratory of Applied Chemistry, Yanshan University , Qinhuangdao 066004, China.
authors.forename: Yufeng
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Applied Chemistry, Yanshan University , Qinhuangdao 066004, China.|Shanghai Electrochemical Energy Devices Research Center, Department of Chemical and Engineering, Shanghai Jiao tong University , Shanghai 200240, China.
authors.forename: Hongnan
authors.initials: H
authors.lastname: Ma
authors.affiliation: Key Laboratory of Applied Chemistry, Yanshan University , Qinhuangdao 066004, China.
authors.forename: Shifei
authors.initials: S
authors.lastname: Huang
authors.affiliation: Key Laboratory of Applied Chemistry, Yanshan University , Qinhuangdao 066004, China.
authors.forename: Xuejiao
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Applied Chemistry, Yanshan University , Qinhuangdao 066004, China.
authors.forename: Meirong
authors.initials: M
authors.lastname: Xia
authors.affiliation: Key Laboratory of Applied Chemistry, Yanshan University , Qinhuangdao 066004, China.
authors.forename: Yongfu
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Shanghai Electrochemical Energy Devices Research Center, Department of Chemical and Engineering, Shanghai Jiao tong University , Shanghai 200240, China.
authors.forename: Zi-Feng
authors.initials: ZF
authors.lastname: Ma
keywords: Ni−Co hydroxyl carbonate; cycling stability; monolayer; solid-state; supercapacitor