Insights Into the Electrochemical and Magnetic Properties of V ₂ O ₅ : A Combined Experimental and DFT Approach

ABSTRACT

2D layered vanadium pentoxide is a promising electrode material, offering high theoretical capacity and fast ion kinetics due to its unique structure and mixed oxidation states. In this work, we study the magnetic and electrochemical properties of V ₂ O ₅ synthesized by a simple hydrothermal route by a combined experimental and DFT approach. Structural investigations by XRD reveal a Pmn2 ₁ orthorhombic structure, which is further confirmed by DFT studies. Both UV–vis spectroscopy and computational studies unveil the presence of an indirect band gap (∼2.24 eV) and weak ferromagnetism arising due to the oxygen vacancies and unpaired electrons in the V ⁴⁺ oxidation state. In the three‐electrode system, it exhibits a maximum specific capacitance of 238 F/g and a discharge time of 241 s at 0.5 A/g. The remarkable capacity retention of 112% is sustained even after 20,000 cycles at 5 A/g in V ₂ O ₅ . Further, the density of states calculations predict the highest quantum capacitance of 810.5 µF/cm ² at −1.5 V and a surface charge density of −469 µC/cm ² at a negative bias. The strong correlation between experimental measurements and theoretical predictions of magnetic behavior and capacitance of V ₂ O ₅ provides valuable insights into the atomistic origin of these functional properties.