“…Therefore, in order to restrain the occurrence of disproportionation and explore its mechanism, researchers tried the method of element substitution, with the precondition that the hydrogen absorption and desorption ability of the alloy cannot be destroyed. In fact, researchers have tried many substitute elements (Cu, Cr, Mn, Al, Fe, Ni, Ti, Hf, Sc) [ 61 , 62 , 63 , 64 , 65 , 66 , 67 ]. For example, Hf and Zr are in the same main family, and HfCo and ZrCo have the same structure of CsCl.…”