Synthesis of Nb2C MXene-based 2D layered structure electrode material for high-performance battery-type supercapacitors

The supercapacitor is a kind of electrochemical energy storage element, has attracted widespread attention, however, it is limited by a lack of ideal electrode materials with excellent cycle stability and high specific capacitance. To address this issue, we prepared Nb(2)CTx MXene-framework coated with Co3O4 to construct a robust 2D cross-linked structure. In this design, the self-assembly of Co3O4 between Nb2C MXene layers can effectively prevent the self-stacking of MXene sheets. The high conductivity and abundant active groups on the surface of MXenes provide a large number of active sites for the uniform distribution of Co3O4 on Nb2C MXene. The Co-MXene electrode achieves a specific capacitance of up to 1061 F g(-1) at the current density of 2 A g(-1), which is higher than the pure Co3O4 electrode and Nb2C MXene electrode. The asymmetric supercapacitors (ASCs) of Co-MXene//AC delivers specific energy densities (Es) of 60.3, 42.5, 31.0, 19.7 Wh kg(-1) at specific power density (Ps) of 0.67, 2.0, 3.4, and 6.8 kW kg(-1) , respectively. The capacitance retention rate of 93% after 1000 cycles at 5 A g(-1) . The study provides a valuable guideline for fabricating satisfactory electrochemical energy storage devices by a feasible method.

Automated summary

In this study, a robust 2D cross-linked structure was constructed by coating Nb(2)CTx MXene with Co3O4, addressing the issue of limited ideal electrode materials for supercapacitors. The Co-MXene electrode showed a higher specific capacitance compared to pure Co3O4 and Nb2C MXene electrodes. The asymmetric supercapacitors also exhibited high specific energy densities and power densities. This research provides valuable guidance for the fabrication of satisfactory electrochemical energy storage devices.