N, O Co-Doped Porous Carbon Decorated on Porous Graphene for Zinc Ion Hybrid Capacitor

Abstract

Metal–organic frameworks (MOFs) derived porous carbon shows tremendous potential in the energy storage field. Herein, N, O co-doped porous carbon decorated on porous graphene composites is prepared by carbonized MOF/graphene composites with followed activated by KOH. MOF-derived porous carbon decorated on porous graphene not only can improve conductivity, but also enhance structural stability. Due to the 3D porous structure, unique structure and conductive support, suitable specific surface area, and abundant N and O functional groups, the obtained ZGCA electrode shows a high specific capacitance of 284.7 F g⁻¹ at 0.5 A g⁻¹, superior rate performance, and good electrochemical stability. More importantly, the constructed Zn//ZnSO₄//ZGCA-700 zinc ion hybrid capacitor delivers a specific capacity of 184.4 mAh g⁻¹ at 0.1 A g⁻¹ and a high energy density of 147.5 Wh kg⁻¹ at a power density of 80.1 W kg⁻¹. At the same time, the capacity retention rate of the ZGCA electrode is 85.2% after 10,000 cycles. This paper provides new ideas and feasible methods for preparing high-performance MOF-based porous carbon for zinc ion hybrid capacitors.