Nanoparticles of Fe₃O₄ Anchored on Ti₃C₂T_x MXene/rGO Aerogels as Hybrid Negative Electrodes for Advanced Supercapacitors

Rational design of a three-dimensional (3D) hybrid aerogel electrode with high energy storage capacity is challenging. In this study, Ti3C2Tx/rGO/Fe3O4 (Fe-M/G) hybrid aerogels are successfully fabricated by a one-step hydrothermal gelation process, in which both self-assembly induced by ethylenediamine (EDA) and in situ growth of Fe3O4 nanoparticles are involved. Owing to the 3D hierarchical porous structure of the aerogel and intimate anchoring of Fe3O4 nanoparticles on the Ti3C2Tx/rGO (M/G) nanosheets, the Fe-M/G hybrid aerogels deliver an outstanding electrochemical performance with a high areal capacitance of 1250.5 mF cm–2 at 1 mA cm–2 and capacitance retention of 85.8% at 20 mA cm–2 after 5000 cycles. Notably, when Fe-M/G was used as a negative electrode matched with a NiCo2O4/rGO positive electrode, the asymmetric supercapacitor (ASC) exhibits a high areal capacitance of 365 mF cm–2 at 1 mA cm–2 and maintains 84.5% of its initial capacitance at 20 mA cm–2 after 30,000 cycles. Furthermore, the ASC device achieves the remarkable energy density of 130 μWh cm–2 at a power density of 802 μW cm–2. The hybrid aerogel electrode may pave a way for development of high-performance energy storage devices.