Plasma-activated nitrogen-doped carbon cloth/bismuth oxide composite electrodes for enhanced supercapacitor performance

A nitrogen plasma-assisted surface engineering strategy was developed to functionalize carbon cloth (CC) and enhance the growth and distribution of Bi₂O₃ nanoparticles for supercapacitor applications. The plasma treatment introduced abundant nitrogen-containing functional groups and defect sites on the CC surface, which promoted uniform nucleation during the subsequent precipitation–calcination process. The resulting Bi₂O₃@NCC composite exhibited a high areal capacitance of 2788.7 mF cm⁻ 2 at 1 mA cm⁻ 2 and retained 64.2% of this value at 20 mA cm⁻ 2 . The electrode also demonstrated good cycling stability, with 80.1% capacitance retention after 5000 charge–discharge cycles. Electrochemical impedance spectroscopy (EIS) confirmed reduced charge transfer resistance and enhanced ion diffusion kinetics. This work demonstrates a practical and scalable plasma-assisted approach for improving both the performance and durability of carbon-based composite electrodes for energy storage applications.