Big breakthrough for 'massless' energy storage

Date:
March 22, 2021
Source:
Chalmers University of Technology
Summary:
Researchers have produced a structural battery that performs
ten times better than all previous versions. It contains carbon
fiber that serves simultaneously as an electrode, conductor,
and load-bearing material.

Their latest research breakthrough paves the way for essentially
'massless' energy storage in vehicles and other technology.



FULL STORY ========================================================================== Researchers from Chalmers University of Technology have produced a
structural battery that performs ten times better than all previous
versions. It contains carbon fibre that serves simultaneously as an
electrode, conductor, and load- bearing material. Their latest research breakthrough paves the way for essentially 'massless' energy storage in vehicles and other technology.


==========================================================================
The batteries in today's electric cars constitute a large part of
the vehicles' weight, without fulfilling any load-bearing function. A structural battery, on the other hand, is one that works as both a power
source and as part of the structure -- for example, in a car body. This is termed 'massless' energy storage, because in essence the battery's weight vanishes when it becomes part of the load-bearing structure. Calculations
show that this type of multifunctional battery could greatly reduce the
weight of an electric vehicle.

The development of structural batteries at Chalmers University of
Technology has proceeded through many years of research, including
previous discoveries involving certain types of carbon fibre. In
addition to being stiff and strong, they also have a good ability to
store electrical energy chemically. This work was named by Physics World
as one of 2018's ten biggest scientific breakthroughs.

The first attempt to make a structural battery was made as early as 2007,
but it has so far proven difficult to manufacture batteries with both good electrical and mechanical properties. But now the development has taken
a real step forward, with researchers from Chalmers, in collaboration
with KTH Royal Institute of Technology in Stockholm, presenting a
structural battery with properties that far exceed anything yet seen,
in terms of electrical energy storage, stiffness and strength. Its multifunctional performance is ten times higher than previous structural battery prototypes.

The battery has an energy density of 24 Wh/kg, meaning approximately 20
percent capacity compared to comparable lithium-ion batteries currently available. But since the weight of the vehicles can be greatly reduced,
less energy will be required to drive an electric car, for example,
and lower energy density also results in increased safety. And with a
stiffness of 25 GPa, the structural battery can really compete with many
other commonly used construction materials.

"Previous attempts to make structural batteries have resulted in cells
with either good mechanical properties, or good electrical properties. But here, using carbon fibre, we have succeeded in designing a structural
battery with both competitive energy storage capacity and rigidity,"
explains Leif Asp, Professor at Chalmers and leader of the project.



========================================================================== Super light electric bikes and consumer electronics could soon be a
reality The new battery has a negative electrode made of carbon fibre, and
a positive electrode made of a lithium iron phosphate-coated aluminium
foil. They are separated by a fibreglass fabric, in an electrolyte
matrix. Despite their success in creating a structural battery ten
times better than all previous ones, the researchers did not choose
the materials to try and break records - - rather, they wanted to
investigate and understand the effects of material architecture and
separator thickness.

Now, a new project, financed by the Swedish National Space Agency,
is underway, where the performance of the structural battery will be
increased yet further.

The aluminium foil will be replaced with carbon fibre as a load-bearing material in the positive electrode, providing both increased stiffness
and energy density. The fibreglass separator will be replaced with an ultra-thin variant, which will give a much greater effect -- as well
as faster charging cycles. The new project is expected to be completed
within two years.

Leif Asp, who is leading this project too, estimates that such a
battery could reach an energy density of 75 Wh/kg and a stiffness of 75
GPa. This would make the battery about as strong as aluminium, but with
a comparatively much lower weight.

"The next generation structural battery has fantastic potential. If
you look at consumer technology, it could be quite possible within a
few years to manufacture smartphones, laptops or electric bicycles that
weigh half as much as today and are much more compact," says Leif Asp.

And in the longer term, it is absolutely conceivable that electric cars, electric planes and satellites will be designed with and powered by
structural batteries.

"We are really only limited by our imaginations here. We have received
a lot of attention from many different types of companies in connection
with the publication of our scientific articles in the field. There
is understandably a great amount of interest in these lightweight, multifunctional materials," says Leif Asp.

Video: https://www.youtube.com/watch?v=yikwX_ehKAQ ========================================================================== Story Source: Materials provided by
Chalmers_University_of_Technology. Note: Content may be edited for style
and length.


========================================================================== Journal Reference:
1. Leif E. Asp, Karl Bouton, David Carlstedt, Shanghong Duan,
Ross Harnden,
Wilhelm Johannisson, Marcus Johansen, Mats K. G. Johansson, Go"ran
Lindbergh, Fang Liu, Kevin Peuvot, Lynn M. Schneider, Johanna
Xu, Dan Zenkert. A Structural Battery and its Multifunctional
Performance.

Advanced Energy and Sustainability Research, 2021; 2 (3): 2000093
DOI: 10.1002/aesr.202000093 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/03/210322091632.htm

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