Researchers have identified a potential new degradation mechanism for electric vehicle batteries – a key step to designing effective methods to improve battery lifespan.
The researchers, from the Universities of Cambridge and Liverpool, and the Diamond Light Source, have identified one of the reasons why state-of-the-art ‘nickel-rich’ battery materials become fatigued, and can no longer be fully charged after prolonged use. Their results open the door to the development of new strategies to improve battery lifespans.
The lithium-ion batteries used by electric vehicles (EV) are likely to dominate the EV market for the foreseeable future, and nickel-rich lithium transition-metal oxides are the state-of-the-art choice for the positive electrode, or cathode, in these batteries.
Currently, most EV batteries contain significant amounts of cobalt in their cathode materials. However, cobalt can cause severe environmental damage, so researchers have been looking to replace it with nickel, which also offers higher practical capacities than cobalt. However, nickel-rich materials degrade much faster than existing technology and require additional study to be commercially viable for applications such as EVs.
Unlike consumable electronics which typically have lifetimes of only a few years, vehicles are expected to last much longer and therefore it is essential to increase the lifetime of an EV battery.
That’s why a comprehensive, in-depth understanding of how they work and why they fail over a long time is crucial to improving their performance."
Dr Chao Xu, lead author(Department of Chemistry, University of Cambridge)
Click here for the full University of Cambridge article.
Click here for the Nature Materials publication - "Bulk fatigue induced by surface reconstruction in layered Ni-rich cathodes for Li-ion batteries"