http://www.pnas.org/content/106/42/17640.abstract
A little bit of lithium does a lot for hydrogen
QuoteAbstract From detailed assessments of electronic structure, we find that a combination of significantly quantal elements, six of seven atoms being hydrogen, becomes a stable metal at a pressure approximately 1/4 of that required to metalize pure hydrogen itself. The system, LiH6 (and other LiHn), may well have extensions beyond the constituent lithium. These hypothetical materials demonstrate that nontraditional stoichiometries can considerably expand the view of chemical combination under moderate pressure.
Full paper
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2764941/
also see
http://phys.org/news/2009-10-f…bit-lithium-hydrogen.html
For Future Superconductors, a Little Bit of Lithium May Do Hydrogen a Lot of Good
--------------------
QuoteThe pressures involved with metallising pure hydrogen are impractically high, current methods of creating high pressure environments are confined to the realm of research. For more practical methods of creating metallic hydrogen, research is being undertaken to find ways lowering the pressures required for metallisation. One method is to dope the hydrogen with an electropositive element, such as lithium.
LiHn materials are predicted to become stable and metallic at approximately one quarter of the pressure required for pure hydrogen, with the most stable of these, LiH6, being predicted to be super conducting [see above]. Another avenue of doping being explored is using silane, SiH4, in conjunction with molecular hydrogen to also lower the pressures required to form metallic hydrogen by forming a lattice in sheets, similar to graphite [1]. In addition to doping, there is promising research that shows that application of an electric field to aid nucleation could also reduce the pressures required [2]. This research also suggests that this method may create metastable metallic
hydrogen once removed from the external field and the high pressure environment. These methods show promise of being viable methods of economically creating metallic hydrogen. However, this research is very topical and currently none of these have been tested experimentally.
1) - Yao, Y. and D.D. Klug, Silane plus molecular hydrogen as a possible pathway to metallic hydrogen. Proc. Natl. Acad. Sci. U. S. A., Early Ed., 2010(Copyright (C) 2012 American Chemical Society (ACS). All Rights Reserved.): p. 1-6, 6 pp.
2) - Nardone, M. and V.G. Karpov, Electric field induced nucleation: an alternative pathway to metallic hydrogen. arXiv.org, e-Print Arch., Condens. Matter, 2011(Copyright (C) 2012 American Chemical Society (ACS). All Rights Reserved.): p. 1-4, arXiv:1103.0288v1 [cond-mat.mtrl-sci].
QuoteElectric field induced nucleation is introduced as a possible mechanism to realize a metallic phase of hydrogen. Analytical expressions are derived for the nucleation probabilities of both thermal and quantum nucleation in terms of material parameters, temperature, and the applied field. Our results show that the insulator-metal transition can be driven by an electric field within a reasonable temperature range and at much lower pressures than the current paradigm of P >∼ 400 GPa. Both static and oscillating fields are considered and practical implementations are discussed.
------------------------------------
Possibility of obtaining atomic metallic hydrogen by electrochemical method
http://arxiv.org/ftp/arxiv/papers/1312/1312.6851.pdf
This reference explains how metalized hydrogen can be produced through the high gas pressures produced by the capillary action of hydrogen into the fractured lattice structure of nickel and palladium.