Thermodynamic and electric study of the LaNi3,6Al0,4Co0,7Mn0,3 alloy

Improving hydrogen storage properties, as a very interesting energy vector, is the objective of several recent researches. AB(5) compounds, whose prototype compound is LaNi5 and its derivatives, have caught the attention of many researchers especially because they have a storage reversibility of hydrogen at ambient temperature and standard pressure. This paper presents an experimental study of hydrogen storage properties and an electric study of LaNi3.6Al10.4Co0.7Mn0.3 alloy. For this reason, the equilibrium isotherms are traced at different temperatures. The effect of temperature, pressure and coolant flow on the kinetics of the hydrogen absorption was also, studies. X-ray structural analysis indicated the formation of a single-phase orthorhombic structure with lattice parameters: a = 0.7517 nm, b = 0.7459 nm and c = 0.8565 nm. Microstructural study showed a densely packed uniform distribution of grains over the surface of the sample. The Alternative current (a.c.) impedance plots were used as tools to analyze the electrical response of the sample as a function of frequency at room temperature. These plots revealed the presence of a relaxation process, which may be attributed to the same type of charge carrier. The frequency dependent conductivity was found to display the universal dynamic response behavior widely observed in disordered solid electrolytes. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.