Synthesis of coal tar pitch-derived heteroatom-doped porous carbon materials for aqueous zinc-ion hybrid supercapacitors

Abstract

Zinc-ion hybrid supercapacitors (ZHSs), which combine the superiority of batteries and supercapacitors, will become a new development direction in the field of energy storage. The development of ZHSs with high capacity and high stability can be further promoted by heteroatom doping or structural modification of cathode materials. Herein, N,O,P co-doped porous carbon materials were synthesized by a facile method using coal tar pitch as precursor, aluminum phosphate as template, and sodium hydroxide as activator. Due to the high specific surface area and abundant micropores, the heteroatom-doped porous carbon materials were employed as cathode for aqueous ZHSs to study the electrochemical performance. Benefitted from the rich micropores and heteroatom doping, the porous carbon electrodes exhibit an outstanding electrochemical performance and deliver a large specific capacitance of 113.3 mA h g−1 at 0.1 A g−1. In addition, the porous carbon electrode shows a high energy density of 64.9 Wh kg−1 and a high power density of 1.23 kW kg−1, which outperforms most aqueous ZHS energy storage systems previously reported. Interestingly, after 5000 cycles at 1 A g−1, the specific capacity is about 36% higher than the original capacity and the coulomb efficiency still remains nearly 100%. The article may provide a new insight into exploring cathode materials for high-performance aqueous rechargeable zinc-ion energy storage devices.

Keywords

• High electrochemical performance
• Aqueous zinc-ion hybrid capacitor
• Porous carbon
• Cathode material