Januar
Bild des Monats Januar 2025
Comparison of the Degradation Behavior of Cathode Active Materials for Li-ion Batteries
Batteries play a key role in the transition from fossil fuels to sustainable energy sources by efficiently storing energy. Among the various battery types, lithium-ion batteries stand out for their high energy density, making them the most suitable for use in electric vehicles and consumer electronics.
Nickel-rich layered oxides are promising cathode active materials (CAMs) due to their high specific capacity, outperforming alternatives such as lithium manganese rich spinels and lithium iron phosphate olivine phase. However, the increased nickel content in these oxides also leads to accelerated ageing, limiting battery life. Optimization of the particle morphology is critical to achieve a balance between electrochemical performance and CAM lifetime. This study investigates two CAM morphologies: single-crystalline (a) and polycrystalline (b). The polycrystalline CAM has secondary crystal structures that form spherical particles.
Degradation was comparedby cycling both materials in coin cells and performing post-mortem analysis using Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) on Focused Ion Beam (FIB)-prepared craters. ToF-SIMS imaging revealed the distribution of conductive carbon (green), CAM (red), and an electrolyte degradation product (blue) within the electrode sheet. Notably, in the polycrystalline material, the degradation product was also detected within the secondary particle interior, indicating electrolyte penetration and degradation on inner surfaces.
This insight into electrolyte degradation on CAM surfaces helps to find strategies to mitigate such reactions, thereby improving CAM durability.
Dieses Bild wurde eingereicht von Steffen Schröder (AG Prof. Dr. Anja Henß).
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