Hydrogen Gas Phase and Electrochemical Hydriding of LaNi5−xMx (M = Sn, Co, Al) Alloys

Abstract

Hydriding/dehydriding properties of a series of LaNi5 based alloys were compared by applying both hydrogen gas phase and electrochemical hydrogen charge/discharge methods. The highest hydrogen absorption capacity of 1.4 wt.% H2 was found for LaNi4.3Co0.4Al0.3, although LaNi4.8Sn0.2 also reveals comparable hydrogen capacity (>1.3%). A significant difference in the hydriding kinetics was observed for all studied alloys before and after activation. The activated alloys (5 cycles at 65 °C, 40 atm. H2) reach their maximum capacities after less than a minute, whereas the pure LaNi5 alloy needs several minutes for complete hydriding. The electrochemical hydriding/dehydriding behavior of the alloys reveals superior performance of LaNi4.3Co0.4Al0.3 and LaNi4.8Sn0.2 compared to the other compositions studied, as the capacity of LaNi4.8Sn0.2 decreases by only 10% for 60 charge/discharge cycles at a current density of 100 mA/g. Good agreement between the hydrogen sorption kinetics of the alloys obtained electrochemically and from hydrogen gas phase has also been observed.

Mechanochemical Synthesis and Hydrogen Sorption Properties of a V-Ni Alloy

“…As expected, the kinetics becomes faster at a higher temperature, and indeed, 95% of the maximum capacity can be reached in about 3300, 2400 and 1600 s at 120, 140 and 170 °C, respectively. These values are lower than that of pure activated LaNi5, a well-known material for hydrogen storage at room temperature, but are higher than those of non-activated LaNi5 [33].…”

Sustainability applications of rare earths from metallurgy, magnetism, catalysis, luminescence to future electrochemical pseudocapacitance energy storage

“…The mixed rare earth RENi 5 with the ratio La 0.1645 Ce 0.7277 Pr 0.0234 Nd 0.0845 Ni 5 has the highest hydrogen storage capacity, according to numerous experiments. [158][159][160][161] Al and Mn partially replacing Ni can boost cycle stability and decrease reaction equilibrium pressure; Fe, Co, and Cr can partially replace Ni to increase hydrogen storage capacity, as Fe, Co, and Cr exhibit greater electron attraction and considerably increase the number of hydrogen atoms.…”

State of the Art in Development of Heat Exchanger Geometry Optimization and Different Storage Bed Designs of a Metal Hydride Reactor

“…Depending on the specific application, a certain metal hydride can be selected. Thus, LaNi 5 is able to absorb about 1.4 wt.% hydrogen at room temperature with the formation of LaNi 5 H 6 hydride, while magnesium is able to absorb up to 7.6 wt.% hydrogen at a temperature of about 400 °C [ 13 , 14 , 15 ]. Nevertheless, the storage of hydrogen in hydride-forming metals is accompanied with drawbacks, the solution of which has received considerable attention from researchers.…”