Why are lithium battery losses so high on the first cycle?

Mn-Ni lithium batteries lose around 40% of the high capacities for which they are known on the first charge-discharge cycle. Scientists have been trying to find out why for years. A team of researchers from INAC and Leti, in conjunction with a researcher from Russia, have made two major contributions to elucidating the mystery. They did it by combining the precision of RMN spectroscopy and a very sophisticated model.

The researchers worked on an industrial-grade material with a Ni-to-Mn ratio of 30%. The first thing they learned was that the nickel is evenly distributed before cycling, with segregation of the nickel-rich and nickel-poor areas. They also discovered that during cycling, the delithiation that occurs during the first charge causes irreversible damage to the nickel-poor areas of the material, where the loss of capacity is concentrated. The results were published in The Journal of Physical Chemistry C.

Contacts: jean-marie.mouesca@cea.fr ; Michel.bardet@cea.fr

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