Hydrogen storage materials at INCDTIM Cluj - Napoca. Achievements and outlook

Introducing hydrogen fuel to the transportation area poses key challenges for research on hydrogen storage materials. As one of the most promising alternative fuels for transport, hydrogen offers the long-term potential for an energy system that produces near-zero emissions and can be based on renewable energy sources. The Joint Research Centre (JRC), a Directorate-General of the European Commission fosters research for safe methods for storing hydrogen, for use in fuel cells or modified combustion engines in cars and other road vehicles. Hydrogen storage materials focused, in the last 30 years, the attention of the research programs in the many countries. Due to the fast development of the fuel cell technologies, the subject is much more stringent now. For mobile applications to fuel cell powered vehicles, on-board storage materials with hydrogen absorption/desorption capacities of at least 6.5%H are needed. For an efficient storage system the goal is to pack hydrogen as close as possible. Hydrogen storage implies the reduction of an enormous volume of H2 gas (1 kg of gas has a volume of 11 m3 at ambient temperature and pressure). To reach the high volumetric and gravimetric density suitable for mobile applications, basically six reversible storage methods are known today according to A. Zuettel: 1) high-pressure gas cylinders, 2) liquid in cryogenic tanks, 3) physisorbed on a solid surface e.g. carbon-nanotubes 4) metal hydrides of the metals or intermetallic compounds. 5) complex hydrides of light elements such as alanates and boranates, 6) storage via chemical reactions. Recently, the storage as hydrogen hydrates at 50 bar using promoters has been reported by F. Peetom. The paper discusses the feasibility of each of these storing alternatives. The authors presents their experience and results of the work in the field of metal hydrides and application obtained since 1975. All classes of hydrogen absorbing intermetallic compounds were studied: LaNi5, FeTi, Ti- and Zr- based Laves Phases, Mg2Ni, carbon nanostructures, alunates. Production technology of Fe Ti, Ti-Cr-Mn H-storing alloys was worked out. Hydrogen storage containers were built for mixed combustion Diesel engines. The paper gives the recent results of H desorption from NaAlH4. In conclusion one emphasizes that the light element complex hydrides and amides are the most actively studied now as hydrogen storage materials envisaged for applications to on-board applications. It must be added that the hydrogen economy related policy issues, as recommended by the European hydrogen energy experts and stakeholders from industry, institutes and consultants, need to increase the level of education both to provide basic H2 knowledge and to drive the education and stimulate research and development on this topic of extremely high interest