Free-standing graphene/vanadium oxide composite as binder-free electrode for asymmetrical supercapacitor.

Author(s) Deng, L.; Gao, Y.; Ma, Z.; Fan, G.
Journal J Colloid Interface Sci
Date Published 2017 Jun 16
Abstract

Preparation of free-standing electrode materials with three-dimensional network architecture has emerged as an effective strategy for acquiring advanced portable and wearable power sources. Herein, graphene/vanadium oxide (GR/V2O5) free-standing monolith composite has been prepared via a simple hydrothermal process. Flexible GR sheets acted as binder to connect the belt-like V2O5 for assembling three-dimensional network architecture. The obtained GR/V2O5 composite can be reshaped into GR/V2O5 flexible film which exhibits more compact structure by ultrasonication and vacuum filtration. A high specific capacitance of 358Fg(-1) for GR/V2O5 monolith compared with that of GR/V2O5 flexible film (272Fg(-1)) has been achieved in 0.5molL(-1)K2SO4 solution when used as binder free electrodes in three-electrode system. An asymmetrical supercapacitor has been assembled using GR/V2O5 monolith as positive electrode and GR monolith as negative electrode, and it can be reversibly charged-discharged at a cell voltage of 1.7V in 0.5molL(-1) K2SO4 electrolyte. The asymmetrical capacitor can deliver an energy density of 26.22Whkg(-1) at a power density of 425Wkg(-1), much higher than that of the symmetrical supercapacitor based on GR/V2O5 monolith electrode. Moreover, the asymmetrical supercapacitor preserves 90% of its initial capacitance over 1000 cycles at a current density of 5Ag(-1).

DOI 10.1016/j.jcis.2017.06.048
ISSN 1095-7103
Citation Deng L, Gao Y, Ma Z, Fan G. Free-standing graphene/vanadium oxide composite as binder-free electrode for asymmetrical supercapacitor. J Colloid Interface Sci. 2017;505:556-565.

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