Tetra-Heteroatom-Doped Ultra-Mesoporous Carbon from Polyphosphazene for High-Performance Supercapacitors

Applying multi-heteroatoms doping strategy to prepare porous carbon materials with high surface area has been demonstrated to be effective for enhancing electrochemical performance of supercapacitors. In this study, N, P, O, and Si tetra-atoms-doped hierarchically micro-/mesoporous carbon with ultrahigh surface area is fabricated from crosslinked-linear poly(diaryloxyphosphazene) precursor by using silica which serves as both template and dopant. The surface area and heteroatoms doping content of the synthesized carbons are tailored by tuning silica dosage and carbonization temperature. The tetra-atoms-doped mesoporous carbon exhibits an ultrahigh surface area of 3,132 m²/g with enriched heteroatoms content (22 at%), which contribute to the capacitive performance. The as-fabricated tetra-atoms-doped carbon symmetric cell displays outstanding specific capacitance of 288.8 F/g (0.5 A/g) (539.8 F/g in three-electrode system) with high remaining capacitance of 226.1 F/g at 10 A/g and excellent cycling stability (97.7 % capacity retention after 5,000 cycles at 10 A/g). This study suggests an effective multi-heteroatoms-doping approach to synthesize mesoporous carbon materials for high performance electrochemical conversion and storage devices.