A pioneering melamine foam-based electrode via facile synthesis as prospective direction for vanadium redox flow batteries

Among the large-scale energy storage devices, vanadium redox flow batteries (VRFBs) are one of the most promising candidates. Carbon felt and graphite felt have been widely adopted as electrodes, however, poor electrochemical activities and low specific surface areas have limited their rollout in the market. Herein, a brand new type of three-dimensional N, P co-doped/reduced graphene oxide (rGO) coated carbonized melamine foam electrode has been proposed to address the above critical issues. Three-dimensional interconnected network structure provides smooth channels for the electrolyte, rGO can further improve the conductivity of the electrode, and heteroatom doping provides additional reaction sites for conversion reactions. Material and electrochemical characterizations demonstrate that the novel electrode possesses a high specific surface area and excellent electrochemical properties. Benefiting from the elaborate design of the electrode structure, the corresponding VRFB is able to yield an energy efficiency of 74.14% at the current density of 300 mA cm−2, and long-term cycling stability is also proved more than 200 consecutive charge–discharge cycles at 200 mA cm−2 without significant decay. All these show that the derivative of melamine foam has enormous advantages and wide application prospects as novel excellent electrode material.