MXene-transition metal sulfide composite electrodes for supercapacitors: Synthesis and electrochemical characterization

MXenes are gaining attention due to their unique 2D layered structures, but face limitations like restacking. Transition metal sulfides (TMS) are promising for energy applications, yet suffer from poor conductivity and volume changes during ion processes, leading to capacity fading. Therefore, we borrowed the structure of ZIF-L with a large specific surface area to synthesize TMS. Constructing heterostructures with metallic conductive MXenes and electrochemically active TMSs emerges as a promising strategy to enhance electrochemical performance and address these challenges. In the present paper, Ti3C2TX Mxene is successfully combined with TMS by a facile in-situ reaction. Based on the electrochemical analysis, Mxene/CoS/NF heterostructure electrode presents an area capacitance of 0.91 mAh/cm2, which is 9.78 times of that of pure MXene at a current density of 2 mA/cm2. Impressively, the assembled asymmetric supercapacitor retains a commendable 85.21 % of its original capacity even after 10,000 cycles. The power density of the assembled supercapacitor is 49.15 mW cm−3, and the energy density is 1.42 mWh cm−3. This underscores a practical and effective avenue for advancing research on Mxene-based electrodes.