Summary
- PSI researchers developed sustainable process and cathode coating for lithium-ion batteries
- Method stabilizes cathode surface for improved battery efficiency in EVs
- Process involves coating cathode surface with lithium fluoride
- Protective coating allows operation at higher voltages with improved performance
- Coating proved effective in reducing impedance and maintaining capacity retention
Article
A team of researchers at the Paul Scherrer Institute in Switzerland has developed a new sustainable process and cathode surface coating that can enhance the performance of lithium-ion batteries. The initial tests on high-voltage batteries using this method have shown promising results, indicating that it could potentially be used to make lithium-ion batteries for electric vehicles more efficient. Operating at voltages above 4.3 V can lead to chemical and electrochemical degradation at the interface between the cathode and the electrolyte. To address this issue, the research team led by Mario El Kazzi has developed a new method to stabilize the cathode’s surface by coating it with a thin protective layer.
The new process involves a gas called trifluoromethane (CHF3), which is produced as a by-product during the manufacture of plastics like PTFE, PVDF, and foam. The researchers initiated a reaction at 300°C between CHF3 and the thin layer of lithium carbonate on the cathode surface, converting lithium into lithium fluoride (LiF). This conversion allows the lithium atoms to remain as ions, enabling them to move between the cathode and the anode to maintain battery capacity. The findings of this study have been published in the scientific journal ChemSusChem (Wiley), highlighting the success of this innovative approach in enhancing the stability and performance of lithium-ion batteries.
The research team conducted electrochemical tests at high operating voltages to evaluate the effectiveness of the protective coating. The results showed that the protective coating remained stable even at voltages as high as 4.8 V, outperforming batteries with unprotected cathodes. For instance, the impedance of the batteries with the protective coating was around 30% lower after 100 charging and discharging cycles compared to batteries with untreated cathodes. Additionally, the capacity retention of the coated batteries exceeded 94% after 100 cycles without any decrease in charging speed, whereas the untreated batteries only achieved 80% capacity retention.
Mario El Kazzi from the Center for Energy and Environmental Sciences at PSI expressed confidence in the universality of the lithium fluoride protective coating, suggesting that it can be applied to most cathode materials. According to El Kazzi, the protective coating also works effectively with nickel- and lithium-rich high-voltage batteries. The successful development of this innovative process and protective coating paves the way for the potential improvement of lithium-ion batteries, contributing to the advancement of sustainable energy storage solutions for various applications, including electric vehicles and renewable energy systems. Further research and development in this area could lead to more efficient and durable lithium-ion batteries for a greener and more sustainable future.
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