Synthesis of La2MgNi9 hydrogen storage alloy in molten salt


Durger N. B. , ANIK M.

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, vol.45, no.15, pp.8750-8756, 2020 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 45 Issue: 15
  • Publication Date: 2020
  • Doi Number: 10.1016/j.ijhydene.2020.01.049
  • Title of Journal : INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
  • Page Numbers: pp.8750-8756
  • Keywords: Metal hydrides, Electro-deoxidation, Electrochemical reactions, X-ray diffraction, ELECTROCHEMICAL PROPERTIES, TITANIUM-DIOXIDE, PHASE-STRUCTURE, MG, REDUCTION

Abstract

La2MgNi9 alloy is synthesized directly from the sintered mixture of La2O3 + NiO + MgO in the molten CaCl2 electrolyte by the electro-deoxidation method at 740 degrees C and the electrochemical hydrogen storage characteristics of the synthesized alloy are observed. Sintering (at 1200 degrees C for 2 h) converts the hygroscopic La2O3 (by the reaction with NiO) into the non-hygroscopic La2NiO4 and La3Ni2O7 phases. The X-ray diffraction peaks indicate that the electro-deoxidation causes LaOCl, Ni, LaNi5 and even target phase La2MgNi9 to form within 2 h process time. The molten salt synthesis process ends up with the final alloy structure of 79% La2MgNi9 and 21% retained LaNi5. The porous alloy structure (with approximately 31.66 m(2)g(-1) specific surface area) is beneficial for higher hydrogen storage capacity and it is observed that La2MgNi9 alloy has promising discharge capacity which is approximately 280 mAhg(-1). This work clearly indicates that the electro-deoxidation is a very effective method in the synthesis of the hydrogen storage materials. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.