From: Eric Walker
Wikipedia has a discussion of Nickel hydride with several references to recent papers. I'm thinking more in relative terms -- I believe it takes quite a lot of energy to dissolve hydrogen into nickel in comparison to the relative ease with which hydrogen dissolves into palladium (which is sometimes called a "hydrogen sponge"). In his Arata replication, Ahern found that an alloy of mostly nickel with less than 10% Pd takes up more hydrogen than Pd alone. But he also found that hydrogen concentration did NOT correlate to excess energy. However, this was with protium, not deuterium. The highest absorber was not the most active and a low absorber was actually superior. There is a known correlation of excess heat to deuterium concentration in Pd-D experiments, which is completely absent in Ni-H. This is yet another reason, one of many - why consideration of all the evidence, giving no preference to Pd-D, points to many different routes to gain in LENR. In many ways, protium and deuterium as so extremely different in physical properties (especially nuclear properties) that they should be considered to be different elements instead of isotopes of the same element.