Tech Briefs Magazine - February 2024 - 35

its work while dissolved in solution, rather
than as a solid applied to a surface.
" This is a brand new approach to developing
flow battery electrolyte, " said Wei
Wang, a long-time PNNL battery researcher
and the principal investigator of the
study. " We showed that you can use a totally
different type of catalyst designed to accelerate
the energy conversion. And further,
because it is dissolved in the liquid
electrolyte it eliminates the possibility of a
solid dislodging and fouling the system. "
While there are many flow battery designs
and some commercial installations,
existing commercial facilities rely on
mined minerals such as vanadium that
are costly and difficult to obtain. That's
why research teams are seeking effective
alternative technologies that use more
common materials that are easily synthesized,
stable and non-toxic.
" We cannot always dig the Earth for new
materials, " said Imre Gyuk, Director of energy
storage research at DOE's Office of
Electricity. " We need to develop a sustainable
approach with chemicals that we can
synthesize in large amounts - just like the
pharmaceutical and the food industries. "
The work on flow batteries is part of a
large program at PNNL to develop and
test new technologies for grid-scale energy
storage that will be accelerated with
the opening of PNNL's Grid Storage
Launchpad in 2024.
The PNNL research team that developed
this new battery design includes researchers
with backgrounds in organic
and chemical synthesis. These skills came
in handy when the team chose to work
with materials that had not been used for
battery research, but which are already
produced for other industrial uses.
" We were looking for a simple way to dissolve
more fluorenol in our water-based
electrolyte, " said Ruozhu Feng, the first
author of the new study. " The β-cyclodextrin
helped do that, modestly, but it's real
benefit was this surprising catalytic ability. "
The research team has applied for
U.S. patent protection for their new battery
design.
For more information, contact Karyn
Hede at karyn.hede@pnnl.gov; 509-3752144.
3D
Battery Imaging Reveals Real-Time Life of Lithium
Metal Cells
The new method may contribute to batteries with higher capacity and increased safety in
our future cars and devices.
Chalmers University of Technology, Gothenburg, Sweden
A
team from Chalmers University of
Technology has succeeded in observing
how the lithium metal in the cell behaves
as it charges and discharges. The new
method may contribute to batteries with
higher capacity and increased safety in our
future cars and devices.
" We've opened a new window in order
to understand - and in the long term to
optimize - the lithium metal batteries of
the future. When we can study exactly what
happens to the lithium in a cell during cycling,
we gain important knowledge of
what affects its inner workings, " said Aleksandar
Matic, Professor at the Department
of Physics at Chalmers and head of the scientific
study that was recently published in
Nature Communications.
There are high hopes that new battery
concepts, such as lithium metal batteries,
will be able to replace today's Li-ion batteries.
The goal is to develop more energy-dense
and safer batteries that will take us
further at a lower cost - both financially
and environmentally. Solid-state batteries,
lithium-sulphur batteries and lithium-oxygen
batteries are among those being held
up as promising alternatives.
All of these concepts build on the idea
that the battery anode consists of a lithium
metal instead of the graphite that is in today's
batteries. Without graphite, the battery
cell will be lighter, and with lithium
metal as the anode it will also be possible to
Tech Briefs, February 2024
With a specially designed cell and using X-ray tomographic microscopy, the researchers can observe the
inner workings of the battery in real time in 3D. The new method may contribute to batteries with higher
capacity and increased safety in our future cars and devices. (Image: Chalmers University of Technology)
use high-capacity cathode materials. This
makes it possible to achieve three to five
times the energy density.
However, lithium metal batteries have
one crucial problem: When battery is
charged or discharged, the lithium does
not always deposit as flat and smooth as it
should. Often, it forms mossy microstructures
or dendrites, long needle-like structures,
and parts of the deposited lithium
can become isolated and are then inactive.
Dendrites also risk reaching the other battery
electrode and causing a short circuit.
Therefore, it is crucial to understand when,
how, and why these structures form.
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" To be able to use this technology in
the next generation of batteries, we need
to see how a cell is affected by factors
such as current density, the choice of
electrolyte, and the number of cycles.
Now we have a tool to do so, " said Chalmers
researcher Matthew Sadd, lead author
of this new study along with colleague
Shizhao Xiong.
The experiment to observe the formation
of lithium microstructures in a working
cell was conducted at the Swiss Light
Source outside Zurich in Switzerland. In
breathless anticipation, the researchers
prepared a specially designed battery cell
35

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Tech Briefs Magazine - February 2024

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