Scalable synthesis of γ-Fe2O3-based composite films as freestanding negative electrodes with ultra-high areal capacitances for high-performance asymmetric supercapacitors

This paper reports a simple, cost-effective, and environmentally friendly procedure for the synthesis of cellulose/functionalized carbon nanotube (f-CNT)/Fe2O3 (CCF) composite films and their performance as freestanding negative electrodes in supercapacitors. A facile chemical precipitation process was performed at room temperature within a short reaction time without requiring any of the special processing conditions used in the conventional hydrothermal synthesis, making it the most cost-efficient method for the bulk-scale production of sustainable supercapacitors. The binder-free negative electrode with ultra-high active material loading exhibited outstanding areal (9107.1 mF cm(-2)) and volumetric (314 F cm(-3)) capacitances, which were much greater than the values reported previously in the literature for negative electrodes. Moreover, an asymmetric supercapacitor cell featuring cellulose/f-CNT/MnO2 (CCM) and CCF as its positive and negative electrodes, respectively, achieved superior electrochemical performances. Therefore, on account of the economic and environmental superiority of this method and its bulk scalability, this paper provides a simple, eco-friendly, and cost-effective approach for the development of sustainable supercapacitors for practical use.

Automated summary

This paper presents a simple, cost-effective, and environmentally friendly method for synthesizing cellulose/functionalized carbon nanotube/Fe2O3 composite films and examines their performance in supercapacitors. The negative electrode prepared using this method exhibits outstanding capacitance values, advancing the development of sustainable supercapacitors.