Density functional theory calculation for the electronic properties and quantum capacitance of pure and doped Zr2CO2 as electrode of supercapacitors

Defect and doping are effective methods to modulate the physical and chemical properties of materials. In this report, the structural stability, electronic properties, and quantum capacitance (C-diff) of Zr2CO2 MXene are investigated by the introduction of Si, Ge, Sn, N, B, S, and F atoms. The doping of F, N, and S atoms makes the system undergo the semiconductor-to-conductor transition, while the doping of Si, Ge, and Sn atoms maintains the semiconductor characteristics. The B-doped system can be used as cathode materials, while the systems doped by S, F, N, Sn atoms are promising anode materials of asymmetric supercapacitors, especially for the S-doped system. The effect of temperature on C-diff is further explored. The result indicates that the maximum C-diff of the studied systems gradually decreases with the increasing temperature. Our investigation can provide useful theoretical basis for designing and developing the ideal electrode materials for supercapacitors.

Automated summary

Defect and doping can effectively modulate the physical and chemical properties of materials. The introduction of Si, Ge, Sn, N, B, S, and F atoms in Zr2CO2 MXene affects its structural stability, electronic properties, and quantum capacitance. Different dopants lead to different electronic transitions, with B-doped system potentially used as cathode materials and S, F, N, Sn-doped systems as promising anode materials for asymmetric supercapacitors. The temperature also has an impact on the quantum capacitance of the studied systems, with the maximum capacitance decreasing with increasing temperature.