Synergistic effects of MXene and Co3O4 in composite electrodes: High-performance energy storage solutions

The development of high-performance electrode materials is crucial for advancing supercapacitor technology. The two-dimensional layered structure of MXene (Ti₃C₂T_x) presents high conductivity, abundant surface functional groups and accessible ion interaction between layers. However, the MXene suffers from the layer aggregation. To overcome this issue, we synthesized a composite material combining MXene with cobalt oxide (Co₃O₄) to enhance electrochemical performance in supercapacitors. MXene’s two-dimensional layered structure, high conductivity, and abundant surface functional groups allow for efficient ion intercalation, while Co₃O₄ contributes high theoretical capacitance and rich oxidation states. The resulted MXene/Co₃O₄ composite exhibits an impressive areal capacitance of 6.456F/cm² at a current density of 3 mA/cm², maintaining 90.52 % capacitance retention at 30 mA/cm², and 81.37 % capacity after 5000 charge–discharge cycles. Additionally, the asymmetric supercapacitor (ASC) device fabricated using the MXene/Co₃O₄ composite achieves a power density of 6.41 mW/cm² at an energy density of 0.37 mWh/cm², with 82.3 % capacitance retention after 5000 cycles. These results demonstrate that the MXene/Co₃O₄ composite material is a promising candidate for high-performance supercapacitors, offering significant improvements in rate capability and long-term cycling stability.