Enhanced electron conductivity, stability, and electrochemical performance of MXene-coated manganese and iron oxides as negative electrode of supercapacitors

Abstract

The fabrication and characterization of a novel MXene/MnO2/Fe2O3 composite as a negative electrode material for supercapacitors are reported in this study. The MXene is integrated by coating the MnO2/Fe2O3 particles, significantly enhancing the specific capacity. An optimal MXene ratio achieves a remarkable specific charging capacity of 1226.30 mAh g-1 at a current density of 1 A g-1. However, further increasing the MXene content does not result in proportional improvement of electrochemical performances, suggesting that an excessive amount negatively impacts the system. Additionally, an asymmetric supercapacitor (ASC) using nickel-aluminum as the positive electrode and an optimized MXene/MnO2/Fe2O3 composite as the negative electrode is developed. This ASC exhibits an impressive energy density of 61.70 Wh kg-1 and a power density of 426.21 W kg-1, with a capacitance retention of 92.92 % after 25,000 cycles at 0.5 A g-1. These findings suggest that MXene/MnO2/ Fe2O3 composites are promising candidates for high-performance supercapacitor applications.