Defect-Rich Graphene Architecture Induced by Nitrogen and Phosphorus Dual Doping for High-Performance Supercapacitors

Heteroatom modification of graphene is a promising strategy to improve the electrochemical performance of supercapacitors. Herein, the heteroatom (N and P) dual-doped reduced graphene architecture (NP-rGA) is constructed via the combination of ice-template and thermal activation approaches. The interconnected morphology and surface chemical state of NP-rGA is confirmed by various microscopic and spectroscopic analyses. The formation of N- and P-containing functional groups acts as primary electroactive sites for the fast accommodation/relaxation of protons or electrons. Furthermore, NP-rGA exhibits a significant improvement in pseudocapacitive behavior in contrast to rGA, such as high specific capacitance (307.8 F g⁻¹), excellent rate capability (85.7%), and cyclic stability of 100.1% of its initial cycle. These excellent electrochemical evidences can be assigned to the synergistic effect of hierarchical structure and uniform heteroatom (N and P) doping.