In this study, first-principles calculations based on density functional theory (DFT) combined with the pseudopotential method are employed to investigate and compare the electronic properties, structural stability, and energy-storage potential of novel two-dimensional binary transition metal systems, Y2VC2Tx (Tx = O2, F2, and OF) o-MXenes. Structural, mechanical, and dynamical analyses confirm the potential stability of all Y2VC2Tx o-MXenes. Among them, the oxygen-terminated Y2VC2O2 layer exhibits superior energetic and mechanical stability compared to the pristine Y2VC2, fluorinated Y2VC2F2, and mixed-functionalized Y2VC2OF structures. The calculated B/G ratios for Y2VC2, Y2VC2F2, Y2VC2O2, and Y2VC2OF are above 1.75, indicating ductile mechanical characteristics in these systems. Electronic structure analyses conducted using different exchange-correlation schemes (GGA and GGA+HSE06) reveal that the studied o-MXenes behave metallically within the GGA approximation, while under the GGA+HSE06 functional, the materials Y2VC2, Y2VC2F2, Y2VC2OF, and Y2VC2O2 exhibit energy gaps of 1.62, 2.94, 2.27, and 2.48 eV, respectively, confirming their semiconducting nature. The pseudogap positioned closer to the Fermi level in Y2VC2O2 implies higher electronic robustness compared to other variants. In aqueous media, oxygen-terminated surfaces exhibit the strongest electrochemical activity, while pristine Y2VC2 shows the weakest response. Y2VC2O2 and Y2VC2OF consistently function as anodic electrodes, whereas Y2VC2 and Y2VC2F2 act as cathodic electrodes under aqueous conditions. In ionic/organic environments, Y2VC2, Y2VC2O2, and Y2VC2OF maintain anodic behavior, while Y2VC2F2 remains cathodic. Moreover, Y2VC2O2 demonstrates remarkable quantum capacitance and highly tunable electrochemical performance, largely driven by surface functionalization. These enhancements significantly improve the energy-storage capabilities of the materials, positioning o-MXenes as strong candidates for next-generation supercapacitors and battery electrodes.

Functionalization-driven modulation of electronic structure and quantum capacitance in o-MXene Y₂VC₂T_x (T_x = O₂, F₂, and OF) for high-performance energy storage

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2026年5月20日

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Navid Mokhtaripoor,
Peiman Amiri,
Amir Aliakbari

摘要

In this study, first-principles calculations based on density functional theory (DFT) combined with the pseudopotential method are employed to investigate and compare the electronic properties, structural stability, and energy-storage potential of novel two-dimensional binary transition metal systems, Y₂VC₂T_x (T_x = O₂, F₂, and OF) o-MXenes. Structural, mechanical, and dynamical analyses confirm the potential stability of all Y₂VC₂T_x o-MXenes. Among them, the oxygen-terminated Y₂VC₂O₂ layer exhibits superior energetic and mechanical stability compared to the pristine Y₂VC₂, fluorinated Y₂VC₂F₂, and mixed-functionalized Y₂VC₂OF structures. The calculated B/G ratios for Y₂VC₂, Y₂VC₂F₂, Y₂VC₂O₂, and Y₂VC₂OF are above 1.75, indicating ductile mechanical characteristics in these systems. Electronic structure analyses conducted using different exchange-correlation schemes (GGA and GGA+HSE06) reveal that the studied o-MXenes behave metallically within the GGA approximation, while under the GGA+HSE06 functional, the materials Y₂VC₂, Y₂VC₂F₂, Y₂VC₂OF, and Y₂VC₂O₂ exhibit energy gaps of 1.62, 2.94, 2.27, and 2.48 eV, respectively, confirming their semiconducting nature. The pseudogap positioned closer to the Fermi level in Y₂VC₂O₂ implies higher electronic robustness compared to other variants. In aqueous media, oxygen-terminated surfaces exhibit the strongest electrochemical activity, while pristine Y₂VC₂ shows the weakest response. Y₂VC₂O₂ and Y₂VC₂OF consistently function as anodic electrodes, whereas Y₂VC₂ and Y₂VC₂F₂ act as cathodic electrodes under aqueous conditions. In ionic/organic environments, Y₂VC₂, Y₂VC₂O₂, and Y₂VC₂OF maintain anodic behavior, while Y₂VC₂F₂ remains cathodic. Moreover, Y₂VC₂O₂ demonstrates remarkable quantum capacitance and highly tunable electrochemical performance, largely driven by surface functionalization. These enhancements significantly improve the energy-storage capabilities of the materials, positioning o-MXenes as strong candidates for next-generation supercapacitors and battery electrodes.

Functionalization-driven modulation of electronic structure and quantum capacitance in o-MXene Y2VC2Tx (Tx = O2, F2, and OF) for high-performance energy storage

摘要

Functionalization-driven modulation of electronic structure and quantum capacitance in o-MXene Y₂VC₂T_x (T_x = O₂, F₂, and OF) for high-performance energy storage