Electrostatic self-assembly assisted construction of MXene/MoO₃ hybrid aerogel for free-standing supercapacitor electrodes

Designing multi-component coupled hybrid electrode materials serves as an effective strategy to enhance the energy density of supercapacitors, while simultaneously addressing the issues of insufficient interface activity and ion transport. Herein, we present a three-dimensional porous cross-linked MXene/MoO₃ hybrid aerogel (TM-50) synthesized through an electrostatic self-assembly strategy. The porous structure enhances ion transport efficiency, while the incorporation of MXene improves the conductivity of MoO₃. Additionally, the randomly interconnected MoO₃ effectively suppresses the self-stacking of MXene nanosheets. Benefiting from these synergistic effects, the TM-50 hybrid aerogel achieves a specific capacitance of 418.2 C g⁻¹ at 0.5 A g⁻¹ in 3 M H₂SO₄, with 92.7% retention after 10000 cycles. Additionally, the asymmetric supercapacitor assembled from TM-50 and activated carbon achieves an energy density of 20.9 Wh kg⁻¹ at 491.5 W kg⁻¹, retaining 90.3% capacitance after 5000 cycles. Density functional theory (DFT) calculations further confirm that the MXene/MoO₃ hybrid exhibits lower H⁺ adsorption energy and a higher electronic state density near the Fermi level, enhancing its interfacial activity. This controllable approach to developing hybrid aerogels is promising for other MXene-based functional materials in diverse applications.