title: High Volumetric Energy Density Asymmetric Supercapacitors Based on Well-Balanced Graphene and Graphene-MnO2Electrodes with Densely Stacked Architectures.
abstract: The well-matched electrochemical parameters of positive and negative electrodes, such as specific capacitance, rate performance, and cycling stability, are important for obtaining high-performance asymmetric supercapacitors. Herein, a facile and cost-effective strategy is demonstrated for the fabrication of 3D densely stacked graphene (DSG) and graphene-MnO2(G-MnO2) architectures as the electrode materials for asymmetric supercapacitors (ASCs) by using MnO2-intercalated graphite oxide (GO-MnO2) as the precursor. DSG has a stacked graphene structure with continuous ion transport network in-between the sheets, resulting in a high volumetric capacitance of 366 F cm-3, almost 2.5 times than that of reduced graphene oxide, as well as long cycle life (93% capacitance retention after 10 000 cycles). More importantly, almost similar electrochemical properties, such as specific capacitance, rate performance, and cycling stability, are obtained for DSG as the negative electrode and G-MnO2as the positive electrode. As a result, the assembled ASC delivers both ultrahigh gravimetric and volumetric energy densities of 62.4 Wh kg-1and 54.4 Wh L-1(based on total volume of two electrodes) in 1 m Na2SO4aqueous electrolyte, respectively, much higher than most of previously reported ASCs in aqueous electrolytes.
authors.affiliation: Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin, 150001, China.
authors.forename: Lizhi
authors.initials: L
authors.lastname: Sheng
authors.affiliation: Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin, 150001, China.
authors.forename: Lili
authors.initials: L
authors.lastname: Jiang
authors.affiliation: Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin, 150001, China. weitong666@163.com.
authors.forename: Tong
authors.initials: T
authors.lastname: Wei
authors.affiliation: Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin, 150001, China. fanzhj666@163.com.
authors.forename: Zhuangjun
authors.initials: Z
authors.lastname: Fan
keywords: graphene; high volumetric energy density; supercapacitors