An MXene/Poly(vinyl alcohol)/Reduced Graphene Oxide Nanocomposite Aerogel as an Ultra-stable Electrode for Capacitive Storage

Currently, high-performance energy storage devices have requirements for electrode materials such as high power density, good stability, and high storage efficiency in various applications. The restacking of two-dimensional MXene nanosheets significantly impacts the performances of energy storage devices. Although three-dimensional (3D) electrode structures exhibit enhanced energy storage capacities, they possess poor stabilities and low storage efficiencies. These issues are addressed in the current study using a directional freeze-drying method and a one-step hydrothermal process to fabricate a nanoscale porous interconnected MXene/PVA (poly(vinyl alcohol))/rGO (reduced graphene oxide) composite aerogel electrode for supercapacitor applications. The rGO provides a stable conductive skeleton, while the hydrophilic PVA acts as a binder to strengthen the interactions between MXene and rGO, and contributes to the capacitance after carbonization. The resulting 3D composite aerogel increased the interlayer spacing of the Ti3C2Tx MXene, enabling efficient electrolyte penetration and ion transport. Due to the synergistic effect of the MXene pseudocapacitance and the rGO double-layer capacitance, the prepared aerogel exhibited a maximum specific capacitance of 489.7 F g–1 at a scan rate of 2 mV s–1. Furthermore, it demonstrated an excellent energy density of 30.2 W h kg–1 at a power density of 2040 W kg–1. After 10,000 charge/discharge cycles at a current density of 10 A g–1, the capacitance retention rate increased slightly to ∼103.85%, representing an excellent cyclic performance. This study offers an effective solution for MXene-based composite aerogel electrodes, meeting the demands of high-performance energy storage and guiding future material optimization.