title: Tungsten oxide@polypyrrole core-shell nanowire arrays as novel negative electrodes for asymmetric supercapacitors.
abstract: Among active pseudocapacitive materials, polypyrrole (PPy) is a promising electrode material in electrochemical capacitors. PPy-based materials research has thus far focused on its electrochemical performance as a positive electrode rather than as a negative electrode for asymmetric supercapacitors (ASCs). Here high-performance electrochemical supercapacitors are designed with tungsten oxide@PPy (WO3 @PPy) core-shell nanowire arrays and Co(OH)2 nanowires grown on carbon fibers. The WO3 @PPy core-shell nanowire electrode exhibits a high capacitance (253 mF/cm2) in negative potentials (-1.0-0.0 V). The ASCs packaged with CF-Co(OH)2 as a positive electrode and CF-WO3 @PPy as a negative electrode display a high volumetric capacitance up to 2.865 F/cm3 based on volume of the device, an energy density of 1.02 mWh/cm3 , and very good stability performance. These findings promote the application of PPy-based nanostructures as advanced negative electrodes for ASCs.
authors.affiliation: National Center for Nanoscience and Technology (NCNST), No.11 ZhongGuanCun BeiYiTiao, 100190, Beijing, P.R. China.
authors.forename: Fengmei
authors.initials: F
authors.lastname: Wang
authors.forename: Xueying
authors.initials: X
authors.lastname: Zhan
authors.forename: Zhongzhou
authors.initials: Z
authors.lastname: Cheng
authors.forename: Zhenxing
authors.initials: Z
authors.lastname: Wang
authors.forename: Qisheng
authors.initials: Q
authors.lastname: Wang
authors.forename: Kai
authors.initials: K
authors.lastname: Xu
authors.forename: Muhammad
authors.initials: M
authors.lastname: Safdar
authors.forename: Jun
authors.initials: J
authors.lastname: He
keywords: asymmetric supercapacitors; core-shell structures; nanowires; negative electrodes; polypyrrole; positive electrodes