A palladium hydride superconductor, Pd^yH_x where ^yH_x is ¹H_x, ²H_x, or ³H_x, having a critical temperature T_c11K and stoichiometric ratio x1. The critical temperature is proportional to a power of the stoichiometric ratio, which is stable over periods exceeding 24 hours, temperature variations from 4K to 400K, and pressures down to 1 mbar. The palladium hydride is coated with a stabilizing material such as a metal, metal oxide, ceramic, or polymer that can bond to palladium. It can be made by electrochemically loading a palladium lattice with isotopic hydrogen in an electrolytic solution, by allowing isotopic hydrogen to diffuse into a palladium thin film in a pressure chamber, or by injecting isotopic hydrogen into a palladium thin film in a vacuum chamber. The stabilizing material can be electrochemically bonded to the surface of the palladium hydride, or deposited using chemical vapor deposition or molecular beam epitaxy.