Electrochemical performance of CeO2/MXene nanocomposites with enhanced capacitance and cycling stability for high-performance supercapacitors

Abstract

Supercapacitors play a crucial role in advancing modern electronic and electrical systems due to their high-power density, rapid charge–discharge rates, and long cycle life. However, achieving optimal electrochemical performance requires the development of advanced electrode materials. MXenes, a class of two-dimensional transition metal carbides or nitrides, have attracted considerable attention for energy storage applications owing to their excellent electrical conductivity, hydrophilicity, and tunable surface terminations. Incorporating MXene into CeO₂-based composites enables the exploitation of these properties to enhance charge storage and transport capabilities. In this study, CeO₂/MXene-based nanocomposites with varying MXene contents (CeO₂, CeO₂/MXene-5, CeO₂/MXene-6, and CeO₂/MXene-7) were synthesized via a hydrothermal method. The structural, morphological, and electrochemical properties of the composites were characterized using advanced analytical techniques. Electrochemical measurements in a three-electrode configuration demonstrated that the CeO₂/MXene-7 composite delivered an outstanding specific capacitance of 1459 F g⁻¹, along with the lowest charge-transfer resistance among all samples. Moreover, it exhibited excellent rate capability and retained 88% of its initial capacitance after 7000 cycles, indicating superior cycling stability. The uniform dispersion of CeO₂ nanoparticles on the MXene nanosheets improved the overall electrical conductivity, thereby facilitating efficient charge storage and transport. These results identify the CeO₂/MXene-7 composite as a promising electrode material for pseudocapacitors, with significant potential for high-performance energy storage applications.