Researchers introduced a process for producing boundary-free single crystal cathodes that operate at high voltage with a magnificent storage capacity
The conventional NMC cathode in Lithium-ion batteries cannot operate in a high voltage environment as cracks are formed due to boundary formation in cathode particles due to the process of charge-discharge cycling, this instantly reduces the performance of the cathode. The researchers involved single crystal practice to avoid this cracking, the team implemented a method for developing boundary-free single crystals that operate at very high voltage and exhibit amazing storage capacity with no loss in performance over 100 cycles of testing.
“The present-day NMC cathode has posed a major barrier to operation at high voltage,” said Guoliang Xu, assistant chemist. With charge-discharge cycling, performance rapidly declines due to cracks forming in the cathode particles. For several decades, battery researchers have been seeking ways to eliminate these cracks.
The testing of small cells with developed single crystal cathode at very high voltage revealed a 25% increase in energy storage per unit volume without affecting performance over 100 cycles of testing. While using NMC cathodes composed of a single crystal with coated polycrystals showed a decrease in capacity by 60% to 80%. As boundaries within the cathode materials lead to performance degradation. Eliminating the boundaries avoids oxygen release and assures the cathode’s safety and stability with cycling.
“We now have guidelines that battery manufacturers can use to prepare cathode material that is boundary-free and works at high voltage,” said Khalil Amine, an Argonne Distinguished Fellow. “And the guidelines should apply to other cathode materials besides NMC.”
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