Gelatin and iron salts will help to efficiently convert human body heat into electricity

Material engineers
developed
the thermoelectric Converter
on
gelatin-based and
salts of iron and potassium.
Device
can transform the warmth of human
body
electricity
record efficiency
providing
voltage
2.2 volt. It
perhaps due to the synergy of the two effects
— thermal diffusion
and termogalvanic facilities. A study published in
journal
Science.

Getting
electricity by the heat of human
body is one of the most
interesting problems of modern
materials science.Such converters need to supply Autonomous
wireless
sensors, and other wearable devices
however
make them work hard, so
the difference
human body temperature and
the surrounding space is small.
Traditional
thermoelectric converters
on the basis of narrow-gap semiconductors
have
low thermoelectric
ratio
Seebeck (about
100
microvolts per Kelvin),
so
their work requires a large temperature difference. To power
simple
sensor
from the heat of the human body need
it would be at the same time
use
a few
thousand
these converters.

Now scientists are developing
thermoelectric
converters
ionic basis,
which can work by two
different mechanisms termogalvanic facilities
and thermal diffusion. In
termogalvanic facilities converters
electricity
get
from
redox reactions
between the two electrodes is cold
hot.
Thermal diffusion
converters work
account
movement
charged particles under the action of
temperature gradient.
Ion
converters much
more effective semiconductor and
show
ratio
Seebeck of the order of millivolts
per Kelvin.

The materials scientists under the leadership of Wei Shu
Liu (Liu Weishu) from the southern University of science and technology in Guangdong and Ghana by Chen (Chen Gang) from mit have designed a
the thermoelectric Converter,
which combines both mechanisms:
termogalvanic facilities and thermal diffusion.
Converter
consists of two identical copper
electrodes, the space between them
gel filled
a mixture of gelatin
and water. One
of the electrodes is placed closer to
the human body, it heats up, while
the other remains cold.

In
as redox
pair used
the mixture
hexacyanoferrate iron K4Fe(CN)6
and
K3Fe(CN)6.

In
the first salt of iron is in the degree
oxidation +2, and the second — degree
oxidation of +3, due to the different energies of solvation of these two salts can be converted into each other. The “hot” electrode
Fe2+
oxidized
to
Fe3+,
giving
one electron, and
on
cold Fe3+
restored
to Fe2+
getting
the electrons from the electrode,
the result between the electrodes is formed
the potential difference. Thermal diffusion
effect
provide
soluble
salts of alkali metals under
the influence of temperature gradient and anions and cations of these salts are moving from
hot
electrode to the cold,
however, the speed
their diffusion
not the same.
In order to
termogalvanic facilities to strengthen the effect
from the reaction
between
hexacyanoferrate,
need
salt with the more mobile cation in
this case created thermodiffusional
the difference
potentials will have the same sign,
what
and termogalvanic facilities.

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