Amino-functionalized and Na⁺ pre-intercalated three-dimensional Ti₃C₂T_x film aerogel with excellent electrochemical performances for supercapacitor

Precise modulation of the pore structure and modification of the surface groups (–NH₂) of MXene aerogels by the solid foaming method in combination with Na⁺ pre-intercalation can significantly increase the layer spacing and change the electronic structure of MXene, thereby significantly optimizing its electrochemical performance. The three-dimensional (3D) network structure provides numerous active sites on the surface of MXene and provides more ion transfer pathways and the large layer spacing allows electrolyte ions fast transport and the surface groups provide more active sites for the pseudocapacitive reaction. As a result, the prepared Na-Ti₃C₂T_x (where T is –O, –OH, –F, and/or –NH₂, and x represents the number of such groups) film aerogel delivers a high mass specific capacitance of 560 F·g⁻¹ and excellent cycling performance of 94.5% capacitance retention after 12,000 cycles in 0.5 M H₂SO₄. In addition, the flexible all-solid-state supercapacitor (ASC) composed of MXene film electrodes has excellent specific capacitance ~ 277 F·g⁻¹ and high energy density ~ 52.8 Wh·kg⁻¹ at 1600 W·kg⁻¹. Therefore, this work not only proposes a feasible synthetic method that can precisely regulate the pore structure and surface features of film aerogels, but also demonstrates the broad application prospects of aerogel materials in wearable power devices.