Nanoarchitectonics and Electrochemical Behavior of Cu Doped h-MoO3 as an Electrode Material for Energy Storage Applications

Enhanced Hydrogen-Ion Storage Performance of Molybdenum Trioxide Nanoribbons Doped by Oxygen Vacancies

Hydrogen ion has been extensively studied as a charge carrier in electrochemical energy storage devices due to its minimal ionic radius and abundant reserves. Among various candidate materials, molybdenum trioxide (MoO3) stands out as a promising electrode material owing to its excellent chemical stability and ultrahigh theoretical storage capacity. However, its practical application is hindered by a narrow potential window as a hydrogen-ion electrode and a low operating voltage caused by aqueous electrolyte decomposition. In this study, MoO3 nanoribbons with significant number of oxygen vacancies were synthesized via a simple hydrothermal method, which exhibit notable backward shift in the hydrogen evolution potential, three-proton intercalation/deintercalation process, and then a very noticeable enhancement in hydrogen-ion storage capacity during electrochemical testing in the aqueous electrolyte. It was also found that tungsten(W) doping in a specific amount can enrich the oxygen vacancies in MoO3 nanoribbons and then further enhance their hydrogen-ion storage performance. Remarkably, the W-doped MoO3 nanoribbons with a nominal molar ratio of 3% demonstrate an exceptional specific capacity of 390.8 mA h/g at a current density of 100 C (40 A/g). This study might highlight the significant impact of oxygen vacancy and tungsten(W) doping on the microstructures and electrochemical properties of MoO3 nanoribbons and provide valuable insights for the design and development of high-performance electrode materials for hydrogen-ion batteries.

Electrical conductivity and electrochemical studies of Cr-doped MoO3 nanoflakes for energy storage applications

The growing demand for electricity has increased the interest of the researchers towards exploration of energy storing devices (ESDs). With the motif for developing electrochemical energy storage devices, this research work is focussed on the study of MoO₃ nanoparticles and its doping with chromium as an efficient electrode material for energy storage applications. The nanoparticles were synthesized by hydrothermal method and were examined by powder X-ray diffraction, which determined the thermodynamically stable orthorhombic phase of MoO₃, and their morphologies were examined using scanning electron microscopy displaying flake-like structures. The typical vibrational bands of Mo-O were identified from Infra-red and Raman spectral analysis. The ultra violet diffuse reflectance spectra revealed the decrease in optical band gap after doping with chromium. The temperature dependent AC and DC conductivities were enhanced on doping. Electrochemical behaviour of the nanoparticles was probed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) measurements and galvanostatic charge-discharge (GCD) analysis for which specific capacitance (C _sp) value of 334 Fg^-1 was achieved for Cr-doped MoO₃ nanoparticles. The electrochemical performance of the sample was found to be increased after doping with Cr.