N, O, P-doped porous carbon with high surface utilization and long cycling life for supercapacitors

The development of miniaturized and lightweight supercapacitors (SCs) becomes a hot research region. Improving the surface area utilization of porous carbon materials can effectively promote the energy density and power density of SCs. This work first constructs three-dimensional porous poly(p-phenylenediamine) hydrogel through adding phytic acid. Thereafter, N, O, P-doped porous carbon (NOPPC) was obtained via simple one-step pyrolysis treatment. The unique three-dimensional porous structure of NOPPC inherited from poly(p-phenyl-enediamine) hydrogel provides plentiful ion storage space and ion transportation channels. Heteroatom-doped feature endows NOPPC with good wettability and more active surface area. The surface utilization of NOPPC-800 reaches up to 2.56 F m- 2, which is better than many carbon materials in literatures. NOPPC-800 can still maintain 135 F g-1 at 20 A g-1. The capacity retention ratio of NOPPC-800 can reach up to 93.4 % after 10000 cycles at 10 A g-1. The quantitative analysis of energy storage mechanism of NOPPC illustrates the synergistic impact of pore structure and doped heteroatoms. These electrochemical results show that NOPPC possesses good practical application value. NOPPC-800//NOPPC-800 supercapacitor shows high energy density and excellent cycle stability. The results show that the balance of heteroatom content, specific surface area and conductivity is the key to obtain promising carbon electrode materials and can be realized via tuning carbonization temperature. This work also demonstrates that rational structure control of carbon precursor is the effective way to promote the capacity of carbon materials.