Metal hydrides in engineering systems, processes, and devices: A review of non-storage applications

Metal hydrides have garnered much interest in scientific and engineering communities since their discovery in 1866 because of the wide range of applications they offer (Bowman et al. and Mueller et al.). A comprehensive review of selected applications involving metal hydrides in engineering systems, processes and devices has been presented in this paper. The applications of metal hydrides can be broadly classified into seven distinct categories, which are: 1) thermal systems, 2) energy systems, 3) actuation and sensing, 4) processing, 5) semiconductors, 6) biomimetic and biomedical systems, and 7) nuclear applications in addition to hydrogen storage. There have been several brilliant reviews published on hydrogen storage in metal hydrides. The focus of this review is on non-storage metal hydride applications. The fundamentals and working principles of engineering systems, processes, and devices based on metal hydrides have been concisely provided. Besides hydrogen storage, metal hydrides have been proposed and demonstrated for applications in hydrogen compressors, refrigerators, and actuators. Optical and electrical properties of hydrides can be exploited in the design of sensors and energy efficient windows. The hydriding and dehydriding processes are effective in preparing implants for osseointegration in addition to being economic. Certain hydride materials are more effective neutron moderators compared to the conventional ones in nuclear power plants. All such applications involving metal hydrides are revised and briefly discussed along with their working principles in this article.