Facile synthesis and modification of Fe2O3 nanorod arrays on carbon paper as efficient negative electrodes for supercapacitors

Abstract

In this research, Fe2O3 nanorod arrays grown on carbon fiber paper were studied, and carbon-coated Fe2O3 (Fe2O3 @C) and sulfurized Fe2O3 @C (Fe2O3 @C-S) were fabricated by carbon coating and sulfurization processes. To promote the application of these materials in supercapacitors, their electrochemical properties were systematically investigated. Based on the results, the materials obtained utilized a pseudocapacitive mechanism for energy storage. Specifically, Fe2O3 exhibited a moderate specific capacitance and extraordinary cycling stability, and no degradation was observed after 10,000 cycles. Impressively, sulfurization greatly enhanced the rate capability and specific capacitance of the sample. As a result, Fe2O3 @C-S attained a specific capacitance of 976.4 mF cm–2 at 4 mA cm–2 and a robust rate capability of 97.30% at 20 mA cm–2, outperforming Fe2O3 @C (84.39%) and Fe2O3 (70.55%) and demonstrating good cycling stability (92.9%). Notably, Fe2O3 @C-S was active as a positive electrode material; thus, a symmetric supercapacitor was assembled, which yielded a volumetric energy density of 1.46 mWh cm–3 at 16.71 mW cm–3 and maintained an energy density of 0.91 mWh cm–3 even at 145.63 mW cm–3. Moreover, the device exhibited good cycling stability with a capacity retention of 88.3% after 10,000 cycles at 10 mA cm–2. The integration of Fe2O3 nanorod arrays on conductive substrates, coupled with the above modifications, strongly promoted the material’s energy storage performance. Our study emphasized the significant potential of Fe2O3 @C-S as an efficient electrode material for supercapacitors.