The lack of practical hydrogen storage
materials, even after great efforts by material scientist for many
years, igives great influence on
the commerical development of fuel cell
today.
Hydrogen storage materials under development has
still keeping fundamantal and basic research stages. Targeted
governmental projects for storage materials such as Japanese NEDO's
and US DOE's are reasonably high enough from practical
application viewpoints. However, the present R&D status is far
from the desired target values in that; (1) costs of raw materials
have not been taken into account in that most materials to be
synthesized might be too expensive for mass applications, (2) mass
productivity of naterials practical uses have never
been evaluated. (3) temeprature levels at hydrogen
release is too high for practical uses, (4) hydrogen capacity
is evaluated only by material basis but not by the
available hydrogen-content basis, (5) "reversible" nature for
"on-board" application has not been proven experimentally,
and (6) none of "reversible" material has been demonstrated yet
in practical car applications.
Sodium Borohydride
(NaBH4) has been developed by MERIT since 2000
as the hydrogen storage material suitable for "off-board", "on-site"
and "off-site" regeneration of "spent fuel" in fuel cell
applications. MERIT believes Sodium Borohydride is the most
practical and mass productive material for hydrogen storage.
MERIT has developed Sodium Borohydride as
hydrogen fuel source in PEMFC and hydrogen carrier in
a new fuel cell namaed Direct Borohydride Fuel Cell (DBFC). A new
production and regeneration process has also been developed by MERIT
that is based on the natural resource, Borax and Borate.
Hydrogen generation
What makes this method so special is that when
Borohydride is hydrolyzed with water, it extracts as much hydrogen
from water as it emits in the reaction. That means water is the
resource to generate half of the hydrogen produced through this
process.
DBFC by MERIT
The new fuel cell, DBFC, has a
theoretical voltage of either 1,64V. The reason that a high
theoretical cell voltage can be obtained from this system is, that
hydrogen exists as a negative ion (protide: H-) in the
complex ion of BH4-. The fact which
needs attention is that a protide can release twice as much electron
as a proton. This difference leads to the difference of the
theoretical voltage of an anode: -0,24V vs. -0,828V. Another
advantage of the DBFC is that in comparison with other fuel cells
the cross over phenomenon almost doesn't exist
Please refer to "Why BH4-?"section for
more information about the advantages and the huge application area
for Borohydride fuel.
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