▎ 摘　　要

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 1M Li2SO4 could enhance the operation voltage up to 1.8V, and exhibited a maximum energy density of 18.5Wh/kg which was 3times higher than that in 1M H2SO4. GH//GH in 1M Li2SO4 could maintain an ideal electrical double layer capacitive behavior even at a high scan rate of 500mV/s. Over 92.3% of capacitance was also maintained after cycling 2000times at 50A/ g.