Hydrogen Storage Properties of PMMA Coated MgH2 - Nb2O5 Composite Powder Prepared by High Energy Ball Milling

High temperature of hydrogen desorption from MgH2 (about 350 °C) and its slow kinetics are the main challenges in using this material for solid-state hydrogen storage. This research aims to study the effect of adding Nb2O5 on reducing the temperature of hydrogen desorption and using polymethylmethacrylate (PMMA) coating to prevent the oxidation of MgH2 particles and improve the kinetics of hydrogen desorption. For this purpose, three samples include a: as-received MgH2, b: MgH2 milled for 4 h and coated with PMMA, and c: milled mixture of MgH2 – 5wt. % Nb2O5 and coated with PMMA were produced. The prepared samples were analyzed using TG-DSC, XRD, EDS, and FESEM. The results showed that adding Nb2O5 and coating with PMMA reduces the hydrogen desorption temperature (about 40 °C) compared to the as-received MgH2. The amount of hydrogen desorption up to 310 °C for samples a, b, and c was measured as 2.2, 1.6, and 1.7 wt. %, respectively. The amount of hydrogen desorption after 39 minutes at 310 °C was 3.5, 1, and 1 wt. % for the mentioned samples, respectively. Studying the hydrogen desorption properties of the samples after 45 days showed the positive effect of the PMMA coating in preventing the oxidation of MgH2.