Nitrogen and Phosphorous Co‐Doped Graphene Monolith for Supercapacitors

The co‐doping of heteroatoms has been regarded as a promising approach to improve the energy‐storage performance of graphene‐based materials because of the synergetic effect of the heteroatom dopants. In this work, a single precursor melamine phosphate was used for the first time to synthesise nitrogen/phosphorus co‐doped graphene (N/P‐G) monoliths by a facile hydrothermal method. The nitrogen contents of 4.27–6.58 at % and phosphorus levels of 1.03–3.00 at % could be controlled by tuning the mass ratio of melamine phosphate to graphene oxide in the precursors. The N/P‐G monoliths exhibited excellent electrochemical performances as electrodes for supercapacitors with a high specific capacitance of 183 F g −1 at a current density of 0.05 A g −1 , good rate performance and excellent cycling performance. Additionally, the N/P‐G electrode was stable at 1.6 V in 1  m H 2 SO 4 aqueous electrolyte and delivered a high energy density of 11.33 Wh kg −1 at 1.6 V.