A LaO/MXene composite electrode for supercapacitors with improved capacitance and cycling performance.

Developing efficient electrode materials is a key towards high power electrochemical energy storage devices. Two-dimensional (2D) MXene shows excellent conductivity and electrochemical performance among other materials. However, the restacking of MXene layers may degrade their specific capacity and cycling performance. Considering this challenge, here we have designed a composite made of 2D MXene nanosheets and lanthanum oxide (LaO) nanoparticles to overcome the limitations. The bifunctionality of LaO nanoparticles prevents the restacking of MXene layers and enhances the electrochemical properties of the electrode due to its good Faradic characteristics. The specific capacitance of the LaO/MXene composite electrode is 366 F/g at 1 A/g, which is 4.5 and 3 times higher than those of the individual LaO and MXene. The composite electrode displays a capacitance retention of 96% after 1,000 cycles, which is due to synergistic effects between the two components and indicates the potential of LaO/MXene composite for supercapacitors.