Improving the Thermal Expansion and Capacitance Properties of MoO₃ by Introducing Oxygen Vacancies

Oxygen vacancies have a profound effect on the electric, magnetic, and optical properties of transition-metal oxides, but their effect on thermal expansion properties has rarely been studied. Herein, we report the effect of oxygen vacancies on the thermal expansion properties and capacitance of MoO₃. It is found that the introduction of oxygen vacancies significantly reduces the orthorhombic strain and thermal expansion anisotropy and results in the decrease of the coefficient of thermal expansion by about 30%. Furthermore, the capacitance of MoO₃ can be enhanced by about 323%, which is associated with the increase of layer spacing as well as the increase of conductivity. Reducing the thermal expansion coefficient and enhancing the capacitance of MoO₃ by introducing oxygen vacancies could provide an effective strategy for improving the device performance of related materials, such as supercapacitors.