| New technology
has zero CO2 emissions, conserves resources and significantly reduces cost
DAIHATSU
MOTOR CO., LTD. (Daihatsu) announced today that it has, working with
Japan's National Institute of Advanced Industrial Science and Technology
(AIST), developed a new fundamental fuel cell technology that completely
eliminates the need for platinum, a precious metal that has been an essential
material in the electrode catalyst in conventional fuel cells for automobiles.
The new technology also fixes hydrazine hydrate inside the fuel tank to
ensure its safe use as a fuel, resulting in no CO2 emissions at all.
This proprietary fuel cell technology
provides numerous benefits, including resource conservation, low cost,
high output, and safe and easy fuel handling. The characteristics of the
new fuel cell technology are described below.
Resource Conservation and Low Cost
The fuel cells currently being used
in fuel cell vehicles employ strongly acidic electrolyte membranes and
therefore must possess high corrosion resistance. Consequently, the use
of expensive platinum in the electrode catalyst material is essential.
Additionally, the large amount of platinum that must be used has become
one of the factors hindering the widespread adoption of fuel cell vehicles.
(Amount of platinum used: At least 100 grams per vehicle1)
In contrast, the newly developed
technology uses alkaline electrolyte membranes. This allows inexpensive
metals such as cobalt and nickel to be used as an electrode catalyst (instead
of platinum), and other inexpensive materials to be used in the separator
and other component parts. As a result, it helps conserve valuable resources
of precious metals and significantly reduces cost.
1: Based on a Daihatsu survey
High Output
Conventional fuel cells that use
liquid fuels such as methanol have poor reactivity and thus cannot produce
the output necessary for automobiles. Using hydrazine hydrate, which possesses
excellent reactivity, as the fuel and a newly developed electrode catalyst,
the new fuel cell can produce a high output of 0.5 W/cm2 (as measured by
Daihatsu), which is comparable to the output obtained from a hydrogen fuel
cell using platinum.
Safe and Easy Fuel Handling
Since hydrazine hydrate is a liquid
fuel, it is easy to handle during filling and its energy density is also
high. Furthermore, hydrazine hydrate results in no CO2 emissions at all,
and is an environmentally friendly synthetic fuel.
At the same time, high-concentration
hydrazine hydrate is designated as a poisonous substance2 under the Poisonous
and Deleterious Substances Control Law, and it must be handled under the
same safety standards applicable to gasoline and most industrial chemicals.
With the objective of ensuring safe use, Daihatsu developed a technology
that fixes the hydrazine hydrate inside the fuel tank through the use of
a polymer, minimizing the adverse effects that any dispersed fuel could
have on humans or the environment should the fuel tank be damaged during
a collision, for example, but that makes the required amount of liquid
hydrazine hydrate available in a timely manner for electricity generation
in the fuel cell.
2: When the liquid concentration
exceeds 30%
With the goal of helping to preserve
the global environment, Daihatsu will accelerate further research and development
of this technology. However, since various issues must be resolved, including
improvements in the polymer for fixing the fuel, enhancement of both the
performance and durability of the fuel cell, and establishment of the necessary
infrastructure, Daihatsu hopes to establish wide-ranging partnerships with
relevant parties and proceed with further R&D.
The paper describing this new technology
was acknowledged as a "Hot Paper" in the Angewandte Chemie, a German chemistry
journal noted for its excellent Impact Factor in the field of chemistry.
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