Green In Situ Fabrication of 3D Porous MoO₃/Ti₃C₂T_x Aerogel Films for Enhanced Supercapacitor Performance without Organic Solvents

A synergistic modification strategy is adopted to address the restacking issue of MXene nanosheets and enhance the electrochemical performance of MXene-based electrode materials. 3D porous MoO₃/Ti₃C₂T_x aerogel films are successfully prepared via the in- situ synthesis of MoO₃ nanobelts on Ti₃C₂T_x MXene using (NH₄)₆Mo₇O₂₄·4H₂O as a molybdenum source. This environmentally friendly method, involving freeze-drying and carbonization processes, eliminates the need for organic reagents and complex operations like repeated centrifugation and washing. Besides, the construction of a 3D porous structure and the in-situ introduction of additional pseudocapacitance into MXene as a synergistic modification strategy can effectively improve the restacking of MXene nanosheets, fully expose the electrochemical reaction active sites, and significantly enhance their electrochemical performance. Consequently, the as-fabricated MoO₃/Ti₃C₂T_x aerogel film electrode achieved a specific capacitance of 430.74 F g⁻¹ at 2 mV s⁻¹, a 42.06% improvement compared to the pure MXene film. It also demonstrated good rate performance at high scan-rates (200 mV s⁻¹) and retained 93.10% of its capacitance after 9000 charge–discharge cycles. The excellent electrochemical performances of high specific capacitance and long-cycling stability make the MoO₃/Ti₃C₂T_x aerogel films promising materials for supercapacitors, and the synergistic modification strategy also provides new insights for fabricating highly efficient electrode materials.