▎ 摘　　要

A simple and template-free method for fabrication of a modified porous graphene hydrogel electrode was developed. The method involved adding natural organic phytate in the pure graphene hydrogels. Benefiting from the introduced phosphate groups and positively charged metal ions, the flexible magnesium phytate/graphene (Mg-P/G) hydrogel electrode showed large specific capacitance of 281 F/g with a small charge transfer resistance of 0.3 Omega. Furthermore, the flexible supercapacitor showed prominent cycling stability (about 100% retention in capacitance over 10000 cycles) and excellent mechanical flexibility (about 97.5% of its original capacitance after 500 bending cycles). (c) The Author(s) 2017. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited. All rights reserved.