New comprehensions on structure superiority of asymmetric carbon membrane and controlled construction of advanced hierarchical inner-structure for high performance supercapacitors

• Published in: Microporous and mesoporous materials Vol. 275; pp. 14 - 25
• Main Authors: Wu, Yage, Liu, Zhen, Ran, Fen
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.02.2019
• Subjects: Asymmetric and symmetric; Carbon membrane; Electrochemical behavior; Hierarchical pore structure; Supercapacitors; Carbon membrane; Supercapacitors; Hierarchical pore structure; Asymmetric and symmetric; Electrochemical behavior
• ISSN: 1387-1811; 1873-3093
• DOI: 10.1016/j.micromeso.2018.08.011

In this study, both asymmetric and symmetric carbon membranes are designed and fabricated through liquid-liquid phase separation and solvent evaporation, respectively. In contrast, asymmetric carbon membrane exhibits asymmetric porous structure with 3 D nanoscaled architecture, which facilitates ion transportation by shortening diffusion pathways for charging and discharging process. Meanwhile, PEG is introduced into the casting solution to mediate the pore size to a rational range and enhance the surface area. When the ratio of PEG is 10 wt%, the carbon membrane shows the highest specific surface area and hierarchical porous size. A maximum specific capacitance of 247 F g−1 is achieved at the current density of 0.5 A g−1 with good rate capability in an aqueous electrolyte of 6 mol L−1 KOH within the potential range of −1 to 0 V. Moreover, symmetric supercapacitors device assembled with the prepared carbon membrane achieved high energy density (9 W h kg−1) and power density (400 W kg−1) in 1 M Na2SO4 solution. The high electrochemical performance reveals the advantage of the rational micropore structure, and the asymmetric membrane architecture rose by fast solvents exchanging during phase-separation. [Display omitted] •Both asymmetric and symmetric carbon membranes was fabricated for supercapacitor electrode.•Asymmetric membrane exhibited better porous structure and higher electrochemical performance.•PEG was further used to mediate the pore structure and enhance the supercapacitance.•A maximum specific capacitance of 247 F g−1 was achieved at 0.5 A g−1.•Symmetric supercapacitor device had an energy density of 9 W h kg−1.