Solution-processed RuO2/MXene/polyaniline nanocomposites for high-performance supercapacitor electrodes: synthesis, characterization, and electrochemical evaluation

Energy storage technologies are the best way to meet the world's need for clean and long-lasting energy. Supercapacitors are becoming more popular for storing electrochemical energy because they can hold a lot of power, charge and discharge quickly, and last a long time. But a big problem is still figuring out how to boost their energy density without hurting other performance metrics. Nanocomposite electrode materials that combine the complementary properties of metal oxides, two-dimensional (2D) materials, and conducting polymers offer a compelling solution. In this study, RuO2/MXene nanocomposites were synthesized by a hydrothermal route, followed by in situ polymerization of aniline to incorporate polyaniline (PANI) at tunable concentrations. The structural and morphological properties of the resulting ternary nanocomposites were investigated using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Electrochemical performance was evaluated through cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) measurements, and electrochemical impedance spectroscopy (EIS) in a three-electrode configuration using a KOH electrolyte. The optimized RuO2/MXene/PANI composite demonstrated a high specific capacitance, superior rate capability, and excellent cycling stability over 5,000 charge-discharge cycles. The incorporation of MXene significantly enhanced electrical conductivity and ion transport, while RuO2 contributed pseudocapacitive charge storage. PANI acted as a flexible conductive binder, further boosting capacitance through faradaic reactions. The synergistic interactions among the three components were confirmed by EIS analysis showing reduced charge transfer resistance. This work demonstrates that rationally engineered RuO2/MXene/PANI ternary nanocomposites are highly effective electrode materials for next-generation supercapacitors. The solution-processing approach adopted here is scalable, cost-effective, and applicable to a broad range of functional oxide-based energy storage systems. These findings open new avenues for designing hybrid nanocomposite electrodes for portable electronics and renewable energy integration.