Facile synthesis of MnO2@Ti3C2Tx composite electrodes for superior performance supercapacitor

Supercapacitors are gaining traction in the energy storage sector due to their high power and energy density. MnO2 is identified as a promising supercapacitors electrode material due to its reversible Faraday reaction and great theoretical specific capacitance. However, its practical performance is hindered by poor electrical conductivity and structural instability. By incorporating Ti3C2Tx, a 2D MXene material known for its high conductivity and functional groups, the electrochemical behavior of the MnO2 composite is expected to be enhanced. This study introduces a novel method for synthesizing MnO2@Ti3C2Tx self-assembled electrodes (1, 3, 6, 9MnO2@Ti3C2Tx composite electrodes) via a simple solution immersion technique at room temperature and ambient pressure. The state of manganese dioxide deposition can be influenced by varying the number of operations of the solution immersion technique. Among them, 6-MnO2@Ti3C2Tx has the largest specific surface area and achieves the best specific capacitance of 324.1 F g- 1. When the current density is increased to 10 A g- 1, the specific capacitance retention of 6-MnO2@Ti3C2Tx is 67.11 %. Furthermore, the 6-MnO2@Ti3C2Tx//Ti3C2Tx asymmetric capacitor demonstrated a maximum energy density of 30.8 W h kg- 1 and a power density of 7493.3 W kg- 1, maintaining a capacitance retention rate of 95.98 % (from 74.6 to 71.6F g- 1) after 2000 chargedischarge cycles. This study presents an effective and scalable synthesis strategy for MnO2 composite electrodes, highlighting their potential for future energy storage applications.