title: Transition metal sulfides grown on graphene fibers for wearable asymmetric supercapacitors with high volumetric capacitance and high energy density.
abstract: Fiber shaped supercapacitors are promising candidates for wearable electronics because they are flexible and light-weight. However, a critical challenge of the widespread application of these energy storage devices is their low cell voltages and low energy densities, resulting in limited run-time of the electronics. Here, we demonstrate a 1.5 V high cell voltage and high volumetric energy density asymmetric fiber supercapacitor in aqueous electrolyte. The lightweight (0.24 g cm(-3)), highly conductive (39 S cm(-1)), and mechanically robust (221 MPa) graphene fibers were firstly fabricated and then coated by NiCo2S4 nanoparticles (GF/NiCo2S4) via the solvothermal deposition method. The GF/NiCo2S4 display high volumetric capacitance up to 388 F cm(-3) at 2 mV s(-1) in a three-electrode cell and 300 F cm(-3) at 175.7 mA cm(-3) (568 mF cm(-2) at 0.5 mA cm(-2)) in a two-electrode cell. The electrochemical characterizations show 1000% higher capacitance of the GF/NiCo2S4 as compared to that of neat graphene fibers. The fabricated device achieves high energy density up to 12.3 mWh cm(-3) with a maximum power density of 1600 mW cm(-3), outperforming the thin-film lithium battery. Therefore, these supercapacitors are promising for the next generation flexible and wearable electronic devices.
authors.affiliation: College of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641, People's Republic of China.
authors.forename: Weihua
authors.initials: W
authors.lastname: Cai
authors.affiliation: College of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641, People's Republic of China.
authors.forename: Ting
authors.initials: T
authors.lastname: Lai
authors.affiliation: College of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641, People's Republic of China.
authors.forename: Jianwei
authors.initials: J
authors.lastname: Lai
authors.affiliation: College of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641, People's Republic of China.
authors.forename: Haoting
authors.initials: H
authors.lastname: Xie
authors.affiliation: College of Materials Science and Engineering, South China University of Technology, Guangzhou, 510641, People's Republic of China.
authors.forename: Liuzhang
authors.initials: L
authors.lastname: Ouyang
authors.affiliation: College of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641, People's Republic of China.
authors.forename: Jianshan
authors.initials: J
authors.lastname: Ye
authors.affiliation: Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Australia.
authors.forename: Chengzhong
authors.initials: C
authors.lastname: Yu