Porous polypyrrole-derived carbon nanotubes as a cathode material for zinc-ion hybrid supercapacitors

Aqueous zinc-ion hybrid supercapacitors (ZISCs) are a kind of energy storage device with promising applications due to their easy assembly, low cost, safety and reliability. Polypyrrole (PPy)-derived carbon is usually used as a cathode material for ZISCs with N-doping originating from the polymer structure and simple preparation. Herein, the porous PPy-derived carbon nanotubes (PCNTs) are prepared by calcination and KOH activation. The microstructure and physicochemical properties of PCNTs can be optimized by regulating the mass ratio of KOH to PPy-derived carbon. The high specific surface area (3537 m2 g-1), hierarchical porous structure, and high contents of O/N-codoping (12.02 at.% and 3.39 at.%), the PCNTs process high specific capacity and excellent cyclic stability. ZISCs based-PCNTs cathode and Zn anode obtain a high specific capacity of 387.8 mAh g-1 at a current density of 0.2 Ag-1, superior rate capability (127.2 mAh g-1 at 20 Ag-1), large energy density (151 Wh kg-1), and power density (12.695 kW kg-1). Furthermore, after 10,000 GCD tested at 5 A g-1, the capacity retention of ZISCs is 90.9 %. This study provides a valuable reference for regulating the microstructure of porous carbon derived from other polymers and promoting its application in aqueous ZISCs.

Automated summary

Porous PPy-derived carbon nanotubes (PCNTs) with optimized microstructure and physicochemical properties were prepared by regulating the mass ratio of KOH to PPy-derived carbon. These PCNTs exhibited high specific capacity and excellent cyclic stability, as well as high energy density and power density. This study provides valuable insights for regulating the microstructure of porous carbon derived from other polymers and promoting its application in aqueous ZISCs.