Single-step fabrication of surface morphology tuned iron oxide anchored highly porous carbon nanotube hybrid foam for a highly stable supercapacitor electrode

The pseudocapacitive metal oxide anchored nanocarbon-based three-dimensional (3D) materials are considered attractive electrode materials for high-performance supercapacitor applications. However, the complex multistep synthesis approaches raise production costs and act as a major barrier to the practical real-world field. To overcome this limitation, in this study, an easily scalable and effective fabrication approach for the development of iron oxide (Fe₃O₄) anchored highly porous carbon nanotube hybrid foam (f-Fe₃O₄/O-CNTF) with micro/mesoporous structure was suggested to improve the durability and energy storage performance. The surface morphology-tuned f-Fe₃O₄/O-CNTF (f-Fe₃O₄/O-CNTF(M)) was fabricated through electromagnetic interaction between the anchored magnetic Fe₃O₄ on the CNT surface and the applied magnetic field. The obtained results clearly demonstrated that the changed surface morphology of the f-Fe₃O₄/O-CNTF(M) strongly affected the meso- and micropore structure, electrochemical performance, and durability. Consequently, the f-Fe₃O₄/O-CNTF(M) showed an almost 120% enhanced specific surface area and nearly 1.9 times increased specific capacitance compared to that of the f-Fe₃O₄/O-CNTF. Furthermore, the changed surface morphology successfully prevented the re-aggregation of the initial structure and significantly improved durability. As a result, f-Fe₃O₄/O-CNTF(M) showed outstanding cycling stability, maintaining almost 100% capacitance retention after 14,000 cycles. Consequently, the assembled symmetric supercapacitor device delivered an energy density of 20.1 Wh·kg⁻¹ at a power density of 0.37 kW·kg⁻¹ with good cycling stability. These results suggest that the f-Fe₃O₄/O-CNTF(M) can potentially be used as an electrode for supercapacitors with good durability.