Ti₃C₂T_x/g-C₃N₄/CNTs Ternary Hybrid Film for All-solid Flexible Supercapacitors and Superb Bandwidth Electromagnetic Wave Absorber

MXene can be used to create bifunctional materials for supercapacitors and electromagnetic wave absorbers by logical composition arrangement and microstructure design. The layered structure, high electrical conductivity, high capacitance, mechanical strength, and flexibility of Ti₃C₂T_x MXene all make it ideal for use as flexible energy storage devices and electromagnetic wave absorbers. In this study, MXene was innovatively intercalated with g-C₃N₄ and CNTs to produce MXCN/CNTs ternary hybrid film. The restacking is successfully avoided, and the layer spacing is increased. Meanwhile, g-C₃N₄ makes the interlayer charge density increase, and CNTs establish the interlayer conducting network, both of which greatly improve the charge transfer efficiency. These ternary hybrid films exhibit superior performance for both supercapacitor electrodes and electromagnetic wave absorbers. The specific capacitance of MXCN/CNTs electrode reaches 477.4 F/g at 1 A/g. The energy density of flexible symmetrical all-solid supercapacitor achieves 25.28 Wh/Kg at 449.99 W/Kg. When bent 180°, the electrochemical performance remains constant. The MXCN/CNTs composites also show excellent electromagnetic wave absorption (EMA) performance. It achieves an optimized absorption intensity of −43.44 dB at 2.6 mm and shows an extremely wide effective absorption bandwidth (EAB) of 8.94 GHz. This work enhances the application studies of Ti₃C₂T_x MXene-based composite materials as multifunctional materials.