Tech Briefs Magazine - December 2023 - BET-21

Improving Battery Performance with More Efficient
Electrodes
A new fabrication approach could make for more efficient batteries that maintain energy and power levels.
Penn State University, University Park, PA
o improve battery performance and
production, Penn State researchers and
collaborators have developed a new
fabrication approach that could make for
more efficient batteries that maintain energy
and power levels.
The improved method for fabricating battery
electrodes may lead to high-performance
batteries that would enable more
energy-efficient EVs, as well as such benefits
as enhancing power grid storage, according
to Hongtao Sun, an Assistant Professor of
industrial and manufacturing engineering at
Penn State, and the co-corresponding author
of the study, which was published in Carbon.
" With current batteries, we want them to
enable us to drive a car for longer distances,
and we want to charge the car in maybe
five minutes, 10 minutes, comparable to
the time it takes to fill up for gas, " Sun said.
" In our work, we considered how we can
achieve this by making the electrodes and
battery cells more compact, with a higher
percentage of active components and lower
percentage of passive components. "
If an electric car maker wants to improve
the driving distance of their vehicles, they
T
add more battery cells, numbering in the
thousands. The smaller and lighter, the better,
according to Sun.
" The solution for longer driving distances
for an electric vehicle is just to add compact
batteries, but with denser and thicker electrodes, "
Sun said, explaining that such electrodes
could better connect and power the
battery's components, making them more
active. " Although this approach may slightly
reduce battery performance per electrode
weight, it significantly enhances the vehicle's
overall performance by reducing the
battery package's weight and the energy
required to move the electric vehicle. "
More efficient electrodes - a kind of
gateway for electricity in a battery - could
help achieve a battery with a higher percentage
of active components.
" If you think about the core components
inside a battery, only the electrode contributes
to the battery performance, " Sun said.
" The other parts like packaging, separator,
current collector and so on, they are all passive
components that add weight and do
not contribute to the battery performance
at all. If we want to improve the battery
performance, we need to work on the battery
electrode materials and maximize their
weight percentage in a battery cell. "
Prior attempts to improve battery performance
via better electrodes focused on
only one metric, which was not as effective
because the battery then performed poorly
on other trade-off metrics. For instance,
when a battery prioritizes high gravimetric
performance (the amount of energy it can
store relative to its weight), it may result
in reduced areal metric performance (how
much charge it can store per unit area) and/
or diminished volumetric performance (the
amount of charge delivered relative to the
battery's size).
Sun and his research team focused on
making thicker electrodes with optimized
charge transport pathways, aiming to enable
high performance across all three
metrics: areal, volumetric, and gravimetric.
To overcome the challenge of a thicker
electrode having poor charge transport kinetics,
the researchers developed a method
to apply Spark Plasma Sintering (SPS) to
electrodes. SPS is an energy-efficient technique
that uses heat and pressure to compact
and densify materials into a solid
object, such as an electrode.
" SPS enabled us to fabricate a very thick
and dense electrode, " Sun said. " The typical
thickness of the battery electrode is only
about 50 microns to 100 microns but now,
in this work, we are talking about 300
microns, 500 microns. That is five times
higher than the proportion of mass of the
electrode in a real battery device. "
Using the researchers' newly designed
Electric field- and pressure-assisted fast sintering to control graphene alignment in thick composite
electrodes for boosting lithium storage performance. (Image: Hongtao Sun, Penn State)
Battery & Electrification Technology, December 2023
thicker electrodes with fast charge transport
capability would increase the percentage
of active components and enhance the
energy capacity normalized by the total
weight of the battery package, Sun said.
They also make the batteries compact due
to the high density of the electrodes, which
enables packing more electrode active materials
within the same space.
For more information, contact Jamie
Oberdick at jco11@psu.edu; 814-8650285.
21

Tech Briefs Magazine - December 2023

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