Theoretical study on the electronic properties and quantum capacitance ofZr₂CO₂MXenewith atomic swap

Abstract

MXenes have the excellent electrochemical properties as electrode of supercapacitors. Using density functional theory, we investigated the electronic properties and quantum capacitance of Zr2CO2 with atomic swap. The atomic swap results in the appearance of Frenkel‐type defect and Schottky defect. The negative binding energy confirms the stability of the studied systems. The atomic swap makes ZrC1, ZrC2, ZrO1, ZrO2, CO2 systems maintain the indirect semiconductor character, and CO2 system has the direct semiconductor character. The thermionic emission performance of Zr2CO2 MXene is greatly improved by atomic swap. ZrO1 and ZrO2 systems in aqueous system are appropriate anode materials. The wide voltage has little effect on the electrode type for perfect Zr2CO2, ZrO1, ZrO2, CO1, and CO2 systems, but changes ZrC1 and ZrC2 systems from cathode material in aqueous system to anode material in ionic/organic system. The work function and effective mass are also explored.

Theoretical Studies on the Quantum Capacitance of Two-Dimensional Electrode Materials for Supercapacitors

“…The maximum C Q of PZ-VC MXene under positive bias is 422 µF/cm 2 (0.53 V), while the maximum C Q of PZ-VO MXene is 359 µF/cm 2 (0.57 V) (Figure 6d,e). Yin et al investigated the C Q of Zr 2 CO 2 with an atomic exchange [125]. According to the plot of C Q -V, they point out that, in the range of ±0.6 V, the C Q of the pristine Zr 2 CO 2 tends to be zero in positive bias, and in negative bias, the highest C Q is 76.8 µF/cm 2 .…”