Resistivity testing of palladium dilution limits in CoPd alloys for hydrogen storage

TL;DR

This study uses resistivity measurements of thin-film CoPd alloys to determine how much palladium can be diluted while still absorbing hydrogen effectively, offering a high-throughput screening method for hydrogen storage materials.

Contribution

It introduces a resistivity-based high-throughput screening technique to evaluate hydrogen absorption in diluted CoPd alloys across the entire composition range.

Findings

Hydrogen absorption detected in alloys with only 20% Pd

Resistivity decreases with hydrogen in diluted alloys, indicating thickness expansion

Resistivity increases in Pd-rich alloys due to hydrogen scattering

Abstract

Palladium satisfies most of the requirements for an effective hydrogen storage material with two major drawbacks: it has a relatively low gravimetric hydrogen density and is prohibitively expensive for large-scale applications. Pd-based alloys should be considered as possible alternatives to a pure Pd. The question is how much one can dilute the Pd concentration in a variety of candidate materials while preserving hydrogen absorption capability. We demonstrate that the resistivity measurements of thin-film alloy samples can be used for a qualitative high-throughput screening and study of the hydrogen-absorbing properties over the entire range of palladium concentrations. Contrary to palladium-rich alloys where additional hydrogen scattering indicates a degree of hydrogen content, the diluted alloy films respond by a decrease of resistance due to their thickness expansion. Evidence of significant hydrogen absorption was found in thin CoPd films diluted to just 20% of Pd.