title: Flexible solid-state supercapacitors based on three-dimensional graphene hydrogel films.
abstract: Flexible solid-state supercapacitors are of considerable interest as mobile power supply for future flexible electronics. Graphene or carbon nanotubes based thin films have been used to fabricate flexible solid-state supercapacitors with high gravimetric specific capacitances (80-200 F/g), but usually with a rather low overall or areal specific capacitance (3-50 mF/cm(2)) due to the ultrasmall electrode thickness (typically a few micrometers) and ultralow mass loading, which is not desirable for practical applications. Here we report the exploration of a three-dimensional (3D) graphene hydrogel for the fabrication of high-performance solid-state flexible supercapacitors. With a highly interconnected 3D network structure, graphene hydrogel exhibits exceptional electrical conductivity and mechanical robustness to make it an excellent material for flexible energy storage devices. Our studies demonstrate that flexible supercapacitors with a 120 μm thick graphene hydrogel thin film can exhibit excellent capacitive characteristics, including a high gravimetric specific capacitance of 186 F/g (up to 196 F/g for a 42 μm thick electrode), an unprecedented areal specific capacitance of 372 mF/cm(2) (up to 402 mF/cm(2) for a 185 μm thick electrode), low leakage current (10.6 μA), excellent cycling stability, and extraordinary mechanical flexibility. This study demonstrates the exciting potential of 3D graphene macrostructures for high-performance flexible energy storage devices.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States.
authors.forename: Yuxi
authors.initials: Y
authors.lastname: Xu
authors.forename: Zhaoyang
authors.initials: Z
authors.lastname: Lin
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Huang
authors.forename: Yuan
authors.initials: Y
authors.lastname: Liu
authors.forename: Yu
authors.initials: Y
authors.lastname: Huang
authors.forename: Xiangfeng
authors.initials: X
authors.lastname: Duan
mesh_terms: D025802:Electric Capacitance; D004553:Electric Conductivity; D004563:Electrochemistry; D006108:Graphite / Q000737:chemistry*; D020100:Hydrogels / Q000737:chemistry*; D011142:Polyvinyl Alcohol / Q000737:chemistry; D013464:Sulfuric Acids / Q000737:chemistry
chemical_list: D020100:Hydrogels; D013464:Sulfuric Acids; D006108:Graphite; D011142:Polyvinyl Alcohol; C033158:sulfuric acid