By Nick
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October 17, 2022
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Scientists have demonstrated a new electrode design that
could propel electric vehicles farther on each charge Photo: Depositphotos
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The work was carried out by scientists at the Skolkovo
Institute of Science and Technology and focuses on one of the battery's two
electrodes, called the cathode. In many lithium-ion batteries, this electrode
is made of layered transition metal oxides known as NMCs that are rich in
nickel and made up of octahedron-shaped particles.
This means that when two of these particles come together,
there are inevitably empty spaces at the boundaries as none will fit together
seamlessly. The scientists were able to alter the configuration of two common
NMCs by tweaking the synthesis procedure, carefully integrating inert salt to
promote the formation of spherical particles over octahedron-shaped ones.
“Our material is a single-crystal NMC with spherical
particles, combining the best of both worlds as far as maximizing density
goes,” explained study co-author Aleksandra Savina. Unlike polycrystals, the
powder particles don’t have internal structure, so there are no wasted spaces
at grain boundaries. But on top of that, you can also pack more spherically
shaped single crystals into the same limited volume than octahedron-shaped
ones, so you get more density on that account, too.”
Microscopic images of the spherical particles making up a
promising new battery electrode Ivan Moiseev et al./Energy Advances
According to the team, this new cathode material offers an
increase in energy density of up to 25%. The scientists suspect that even more
energy can be packed into the same volume through further experimentation with
the particle size, perhaps mixing smaller and larger ones to further increase
the cathode’s density. Another useful feature of the design is the spherical
particles minimize surface contact with the battery’s electrolyte, slowing the
cathode’s degradation.
“Cathode materials are an important bottleneck as far as
electric vehicle batteries are concerned,” said principal investigator Professor
Artem Abakumov. “The cathodes in batteries powering electric cars tend to use
layered transition metal oxides, including nickel-rich ones. We improved two
commonly used materials of this kind, achieving a 10%-25% increase in energy
density. This translates into smaller cathodes, more compact batteries, and
therefore greater energy storage capacity for the same volume. As an added
bonus, the material is slower to deteriorate.”
The research was published in the journal Energy Advances.
Source: Skoltech