Researchers at the Federal Institute for Materials Research and Testing (BAM) have identified a new diagnostic method for tracking lithium-ion battery degradation. By analyzing the distribution of lithium-6 and lithium-7 isotopes, scientists can now create a fingerprint of the specific mechanisms causing battery ageing.
The study focused on batteries with lithium-nickel-manganese-cobalt oxide cathodes and graphite anodes. Tests revealed that lithium-6 accumulates at the anode after initial charge cycles, while lithium-7 increases at the cathode after 280 cycles. These shifts correlate directly with observed capacity loss in the cells.
The team utilized high-resolution mass spectrometry to examine isotope distribution layer by layer within the electrodes. This research was conducted in collaboration with Nu Instruments Ltd. and the Leibniz Institute for Solid State and Materials Research Dresden (IFW Dresden), with findings published in ACS Energy Letters.
This method allows for the identification of degradation processes before significant capacity loss occurs. By using isotopes as natural markers, the researchers aim to improve battery design and provide more accurate predictions regarding the service life of lithium-ion energy storage systems.
