LAUSR

ABSTRACT A simple and environmentally friendly route was developed to synthesize graphene hydrogel (GH) from ascorbic acid with mesoporous structure. The symmetric supercapacitors were packaged using GH as electrodes (GH\\GH). GH\\GH supercapacitor in the neutral aqueous solution electrolytes of 1 M Li2SO4 could enhance the operation voltage up to 1.8 V, and exhibited a maximum energy density of 18.5 Wh/kg which was 3 times higher than that in 1 M H2SO4. GH//GH in 1 M Li2SO4 could maintain an ideal electrical double layer capacitive behavior even at a high scan rate of 500 mV/s. Over 92.3% of capacitance was also maintained after cycling 2000 times at 50 A/ g.