Polyacrylonitrile Derived Porous Carbon for Zinc-Ion Hybrid Capacitors with High Energy Density

Aqueous zinc-ion hybrid capacitors (ZIHCs) attract widespread attention due to their excellent electrochemical performance, safety, and low cost. Here, a honeycomb-like porous carbon is synthesized as the cathode of ZIHCs via facile pre-oxidation in combination with an activation process. The pre-oxidized porous carbon (PPC) displays a larger specific surface area and faster electrochemical kinetics compared to porous carbon without pre-oxidation (PC), realizing a superior electrochemical performance. The PPC cathode can deliver a capacity of 238 mAh g(-1) at 0.1 A g(-1). Besides, the hybrid capacitors can achieve a high energy density of 193.6 Wh kg(-1) at 76.6 W kg(-1) and 109.5 Wh kg(-1) at a maximum power density of 3981 W kg(-1). More importantly, the hybrid capacitor exhibits a good cycling stability with a capacity retention of 83 % after 20000 cycles at a high current density of 2 A g(-1). This cathode material - with an excellent electrochemical performance - could pave the way for application of ZIHCs.