Energy

New electrode wastes no space to offer EV batteries a 25% density boost

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Scientists have demonstrated a new electrode design that could propel electric vehicles farther on each charge
Microscopic images of the spherical particles making up a promising new battery electrode
Ivan Moiseev et al./Energy Advances
Scientists have demonstrated a new electrode design that could propel electric vehicles farther on each charge

Scientists tinkering with commonly used battery materials have come up with a way of tweaking their microstructures to improve energy density. The work points the way to electric vehicles that can travel farther on each charge, with the scientists hopeful further experiments can boost the performance even further.

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

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5 comments
vince
Won't help EV's from Japan. They are mired in mediocrity and the belief that Americans don't need more than 150-200 miles of range. Take for example the Nissan Leaf which offers a 145 mile range with 40 kW battery and 212 miles with the 60 kW battery. Even the much cheaper Chevy Bolt gets 259 miles of range and highway tests at 70 give it a 260 mile range. Highway tests on the Leaf gave it only a 180 mile range. And that's with a NEW battery. In 2 to 3 years with 10 to 15% degradation--the highway range will drop under 150 miles. What good is that in most of the Western states West of the Mississippi? none at all. Honda doesn't even make an EV and Toyota is about to start selling one but at much higher prices than the Chevy Bolt. Kudo's GM for keeping prices affordable for all.
Nobody
All these claims remind me of the flying car or cures for the common cold or cancer. Just around the corner and probably next year.
Username
Maybe it's time to stop covering every claim made of battery improvements and only cover technology that enters production.
DaveWesely
Nobody claims technological progress turns into production results overnight.
Jinpa
To Vince: Honda makes the Insight EV. Hybrids include the Accord, Civic and CR-V. https://automobiles.honda.com/hybrid-family
About 60% of the U.S. population lives east of the Mississippi.