Nitrogen‐Doped Cellulose‐Derived Porous Carbon Fibers for High Mass‐Loading Aqueous Supercapacitors

Abstract Biomass‐based porous carbon with renewability and flexible structure tunability is a promising electrode material for supercapacitors. However, there is a huge gap between experimental research and practical applications. How to maintain good electrochemical performance of high mass‐loading electrodes and suppress the self‐discharge of supercapacitors is a key issue that urgently needs to be addressed. The structure regulation of electrode materials such as heteroatom doping is a promising optimization strategy for high mass‐loading electrodes. In this work, nitrogen‐doped cellulose‐derived porous carbon fibers (N‐CHPCs) were prepared by a facile bio‐template method using cotton cellulose as raw material and urea as dopant. The prepared N‐CHPCs have high specific surface area, excellent hierarchical porous structure, partial graphitization properties and suitable heteroatom content. The assembled high mass‐loading (12.8 mg cm −2 ; 245 μm) aqueous supercapacitor has excellent electrochemical performance, i. e., low open‐circuit voltage attenuation rate (21.39 mV h −1 ), high voltage retention rate (78.81 %), high specific capacitance (295.8 F g −1 at 0.1 A g −1 ), excellent area capacitance (3.79 F cm −2 at 0.1 A g −1 ), excellent cycling stability (97.28 % over 20,000 cycles at 1.0 A g −1 ). The excellent performance of high mass‐loading N‐CHPCs is of great significance for their practical applications in advanced aqueous supercapacitors.