Enhanced supercapacitive performance of manganese oxides doped two-dimensional titanium carbide nanocomposite in alkaline electrolyte

• A novel MnO2–Ti3C2 nanocomposite with layered hybrid structure has been synthesized.
• MnO2 nanoparticles inserted into the Ti3C2 matrix improve electrochemical performance.
• MnO2–Ti3C2 electrode exhibits high rate capability and excellent cycling stability.

Two-dimensional transition metal carbides MXenes, one of promising electrode materials for electrochemical capacitors (ECs), process unique layered structure, high surface area, remarkable chemical stability, and electrical conductivity for energy storage. However, the low capacity of MXene electrodes limits their further application in ECs. Herein, with excellent electrochemical performance of MnO2, Ti3C2 nanosheets decorated with MnO2 nanoparticles were synthesized through a simple liquid phase precipitation method and heat treatment process, and were subsequently employed to the electrode for ECs. TEM and XRD results demonstrate that MnO2 nanoparticles, about 20–40 nm in diameter size, have been homogeneously inserted into the interlamination of Ti3C2 matrix for cation intercalation. Due to the synergistic effect between MnO2 and Ti3C2 matrix, the nanocomposite exhibits a superior areal capacitances of 377 mF cm−2 at scan rate of 5 mV s−1, which is significantly higher than that of Ti3C2 (306 mF cm−2), and shows excellent cycling stability with capacitance retaining 95% after 5000 cycles. Even at a high scan rate of 200 mV s−1 (310 mF cm−2), MnO2–Ti3C2 nanocomposite displays a high rate capability of 83%. These results demonstrate that MnO2–Ti3C2 nanocomposites offer fascinating potential for high-performance ECs.