Source: Chalmers University of Technology
Summary: A new concept for an aluminium battery has twice the energy density as previous versions, is made of abundant materials, and could lead to reduced production costs and environmental impact. The idea has potential for large scale applications, including storage of solar and wind energy.
A new concept for an aluminium battery has
twice the energy density as previous versions, is made of abundant materials,
and could lead to reduced production costs and environmental impact. The idea
has potential for large scale applications, including storage of solar and wind
energy. Researchers from Chalmers University of Technology, Sweden, and the
National Institute of Chemistry, Slovenia, are behind the idea.
Using aluminium battery technology could
offer several advantages, including a high theoretical energy density, and the
fact that there already exists an established industry for its manufacturing
and recycling. Compared with today's lithium-ion batteries, the researchers'
new concept could result in markedly lower production costs.
"The material costs and environmental
impacts that we envisage from our new concept are much lower than what we see
today, making them feasible for large scale usage, such as solar cell parks, or
storage of wind energy, for example," says Patrik Johansson, Professor at
the Department of Physics at Chalmers.
"Additionally, our new battery concept
has twice the energy density compared with the aluminium batteries that are
'state of the art' today."
Previous designs for aluminium batteries have
used the aluminium as the anode (the negative electrode) -- and graphite as the
cathode (the positive electrode). But graphite provides too low an energy
content to create battery cells with enough performance to be useful.
But in the new concept, presented by Patrik
Johansson and Chalmers, together with a research group in Ljubljana led by
Robert Dominko, the graphite has been replaced by an organic, nanostructured
cathode, made of the carbon-based molecule anthraquinone.
The anthraquinone cathode has been
extensively developed by Jan Bitenc, previously a guest researcher at Chalmers
from the group at the National Institute of Chemistry in Slovenia.
The advantage of this organic molecule in the
cathode material is that it enables storage of positive charge-carriers from the
electrolyte, the solution in which ions move between the electrodes, which make
possible higher energy density in the battery.
"Because the new cathode material makes
it possible to use a more appropriate charge-carrier, the batteries can make
better usage of aluminium's potential. Now, we are continuing the work by
looking for an even better electrolyte. The current version contains chlorine
-- we want to get rid of that," says Chalmers researcher Niklas Lindahl,
who studies the internal mechanisms which govern energy storage.
So far, there are no commercially available
aluminium batteries, and even in the research world they are relatively new.
The question is if aluminium batteries could eventually replace lithium-ion
batteries.
"Of course, we hope that they can. But
above all, they can be complementary, ensuring that lithium-ion batteries are
only used where strictly necessary. So far, aluminium batteries are only half
as energy dense as lithium-ion batteries, but our long-term goal is to achieve
the same energy density. There remains work to do with the electrolyte, and
with developing better charging mechanisms, but aluminium is in principle a
significantly better charge carrier than lithium, since it is multivalent --
which means every ion 'compensates' for several electrons. Furthermore, the
batteries have the potential to be significantly less environmentally
harmful," says Patrik Johansson.
From source: https://www.sciencedaily.com/releases/2019/09/190930082249.htm
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