Pyrrolic-Dominated Nitrogen Redox Enhances Reaction Kinetics of Pitch-Derived Carbon Materials in Aqueous Zinc Ion Hybrid Supercapacitors

The development of high-performance, low-cost carbon cathodes is desperately desired but remains challenging for further widespread application of aqueous Zn-ion hybrid supercapacitors (ZHSCs). Herein, we propose nitrogen-doped carbon materials derived from inexpensive industrial byproducts, pitch, as advanced ZHSCs cathodes. The nitrogen dopants significantly enhance the conductivity of pitch-derived carbon while the electrochemically active pyrrolic nitrogen substantially accelerates the reaction kinetics for energy storage and yields more pseudocapacitance via nitrogen redox mechanism. Consequently, the as-designed cathode shows satisfactory Zn ion storage ability as well as distinct anti self-discharge ability resulting. When assembled as a ZHSC device, the supercapacitor delivers a high capacity of 136.2 mA h g–1, excellent rate performance (50.8% capacity retention from 0.3 A g–1 to 15 A g–1) and satisfactory anti self-discharge ability (only 4.6% capacity loss after 24 h rest). This finding highlights the potential high-value utilization of industry byproducts and provides insight for understanding nitrogen redox chemistry in aqueous energy storage.