Chemical Engineering October 2021 - 5

Chementator
A flexible, origami-based fuel cell
U
ntil now, manufacturing polymerelectrolyte
membrane fuel cells
(PEMFCs) that are small, light and
capable of mechanical movement
has been challenging using conventional
methods. PEMFCs are composed of end
plates, bipolar plates, gaskets, membraneelectrode
assemblies (MEAs) and other assembly
parts, of which the end plates and bipolar
plates occupy 80% of the total weight.
Researchers, led by professor Yung-Eun
Sung at the Center for Nanoparticle Research
within the Institute for Basic Science
(IBS; Seoul, South Korea; www.snu.ac.kr)
reported the development of a lightweight
and flexible, passive air-breathing PEMFC.
These new fuel cells, termed tubular PEMFC
(t-PEMFC), are not only lightweight and miniaturized,
but are also flexible in design.
As described in a recent issue of ACS
Energy Letters, the basic unit of
the t-PEMFC has a conical shape,
which allows for simplification
of the components and to facilitate
easier assembly by allowing
the parts to be rolled up and
stacked like paper cups (photo).
This greatly reduces the number
of parts necessary for assembly,
such as clamps and bolts, as well
as removing the bulky end plates
that are used in conventional fuel
cells. Because the inside of the
tube itself can function as a channel,
it also eliminates the need for
a flow field plate. In addition, the
bipolar plate is lightweight and compact
due to being composed of stainless-steel
mesh. As a result, the total weight of the
parts, excluding the membrane electrode
assembly, was reduced to less than 60% of
conventional designs. The conical reverse
truss design allows the PEMFC to be easily
folded and bent using origami principles.
The folding reduces the volume by nearly
50%, and 90-deg bending is possible without
degradation in performance.
The flexible t-PEMFC may have a wide
range of applications in devices that require
mechanical movements, such as drones,
robots, electrical wires, and small pipelines
that require mobility. This technology may
also be applied in electrochemical devices
based on polymer membrane electrodes,
which are used in various processes, including
water electrolysis and CO2 conversion.
IBS
Edited by:
Gerald Ondrey
'NEW FOOD'
GEA AG (Düsseldorf,
Germany; www.gea.
com) has received a contract
from Novozymes
A/S (Copenhagen, Denmark;
www.novozymes.
com) for a turnkey fitting
of a major new plant to
produce plant-based
proteins for the plantbased
food industry. The
high double-digit millioneuro
order contract is
said to be one the largest
in GEA's history. Construction
on the new factory
in Blair, Nebraska will
start later this year, and
is expected to be completed
towards the end
of 2023.
For decades, Novozymes
has been developing fermented
catalytic (that is,
industrially produced)
proteins
- enzymes
- that are the basis for
many industrial applications.
Only recently, the
company announced its
intention to invest DKK2
billion ($320 million) in the
growth market for functional
proteins (advanced
protein solutions) for the
food industry.
(Continues on p. 6)
A solvent-free process makes battery electrodes
C
onventional processes for manufacturing battery
electrodes use toxic solvents and require a
lot of space and energy. In contrast, DRYtraec
- a new dry-coating process developed by the
Fraunhofer Institute for Material and Beam Technology
(IWS; Dresden, Germany; www.iws.fraunhofer.de) - uses
no solvents, is environmentally friendly, cost effective and
can be used on a large scale.
Battery electrodes normally consist of a metal foil with
a thin coating, which contains the active components
that are responsible for storing energy. " The conventional
coating process uses a wet chemical method
that applies what is known as slurry, " explains Benjamin
Schumm, group manager for Chemical Coating Technologies
at IWS. The active material, conductive carbon
and binders are dispersed in a solvent to make a kind of
paste, which is initially applied to the metal foil to form a
wet coating. " Extremely large machines with very long
drying tracks are needed to ensure that the solvent will
evaporate afterward, " he continues. " With DRYtraec, we
CHEMICAL ENGINEERING WWW.CHEMENGONLINE.COM
can design this process more efficiently. "
DRYtraec uses similar raw materials as in the slurry
process, but instead of a solvent, a special binder is
used. These materials form a dry mixture that is fed into
a calender gap - the space between two rollers rotating
in opposite directions. The crucial detail is that one
of the rollers must be turning faster than the other. This
induces a shear force that ensures that the binder forms
thread-like networks (fibrils). The process is designed so
that both sides of the film can be coated simultaneously.
The resulting coil then is cut to the required size. The
process not only eliminated the need for solvent, but also
the final, energy- and time-intensive drying step.
The first prototype DRYtraec systems were commissioned
as part of the DryProTex funding project, which
demonstrated that it is possible to manufacture electrodes
continuously,
regardless of the type of battery.
Discussions are currently underway with several automobile
and cell manufacturers to plan the construction
of a number of pilot systems.
OCTOBER 2021
5
http://www.gea.com http://www.novozymes.com http://www.snu.ac.kr http://www.iws.fraunhofer.de http://WWW.CHEMENGONLINE.COM
Chemical Engineering October 2021

Table of Contents for the Digital Edition of Chemical Engineering October 2021
