Electrospun N‐Doped Carbon–Carbon Nanofibers with Enhanced Porosity for High‐Performance Zinc‐Ion Hybrid Supercapacitor Application

Zinc‐ion hybrid supercapacitors (ZIHSCs) represent a promising frontier in high‐performance energy storage, offering greater energy density characteristic shown by batteries alongside high power yield and extended life of supercapacitors. Carbon materials, due to their inexpensiveness, abundance, and excellent conductivity, have been promising cathode choices for ZIHSCs. However, the application of electrospun carbon nanofibers as cathodes in ZIHSCs remains relatively unexplored. This study describes the synthesis of electrospun porous N‐doped carbon (NC)‐carbon nanofibers (NC‐CNFs) through a carbonization‐activation pathway. The NC‐CNFs achieves specific surface area (SSA) of 2426.6 m 2 g −1 and a specific capacity of 173.5 mAhg −1 at 0.1 Ag −1 in a ZIHSC setup. A maximum energy density (ED) and power density (PD) of 138.8 Wh kg −1 and 7998.9 W kg −1 , respectively is also obtained. After 10 000 charge‐discharge cycles, the device retains 91.7% initial capacitance. Additionally, the charge storage performances of a symmetric supercapacitor (SC) and a ZIHSC, made of NC‐CNFs, are compared to prove the superiority of the ZIHSC over SC. This study highlights that incorporating NC into electrospun carbon nanofibers, with potassium hydroxide (KOH) activation, yields a ZIHSC cathode material with an optimal porous 1D morphology, large SSA, optimized nanofiber diameter, and efficient heteroatom doping, leading to excellent electrochemical performance.