Hierarchical porous carbon with abundant N/O doping as an anode for zinc ion hybrid supercapacitors

Abstract

Aqueous zinc-ion hybrid supercapacitors (ZISCs) known for their affordability, stability, and high energy density represent innovative energy storage devices. Porous carbon is usually used as the cathode material of ZISCs, and its structure significantly affects the dual performance of high power density and energy density of ZISCs. Herein, a one-pot carbonization strategy is proposed, eliminating the need for templates, additional heteroatom compounds, and activation processes. By precisely controlling the temperature to optimize the structure and electrochemical performance of carbon materials, we successfully synthesized hierarchical porous carbon materials (NOPC-800) with a high specific surface area of 1545.7 mg, featuring dual doping of 12.3 at% nitrogen and 13.35 at% oxygen. The self-doping of abundant nitrogen and oxygen atoms facilitates the chemical adsorption of ions and accelerates pseudocapacitive reaction kinetics. Leveraging these advantages, ZISCs were assembled using NOPC-800 as the positive electrode and zinc as the negative electrode, showcasing remarkable performance: a specific capacity of up to 121.9 mAh g, an energy density of 97.5 Wh kg, and a power density of up to 16000 W kg. Remarkably, NOPC-800 maintained an excellent capacity retention of 94.9% after 10,000 cycles at a current density of 10 A g. This research paves an innovative and feasible path for the design and advancement of novel heteroatom-rich carbon cathodes.