Villigen, Switzerland, Researchers at the Paul Scherrer Institute (PSI) have developed a groundbreaking cathode surface coating that enables lithium-ion batteries to operate at voltages of up to 4.8 volts, significantly improving their energy density and efficiency. The new process also utilizes trifluoromethane (CHF3), a potent greenhouse gas, to create the protective layer. Initial tests have shown exceptional results, with capacity retention exceeding 94% after 100 charge cycles, compared to just 80% for uncoated batteries.
The innovative coating process stabilizes the cathode by converting lithium carbonate on its surface into lithium fluoride (LiF) through a reaction at 300°C using CHF3, a byproduct of plastic manufacturing. This protective layer minimizes degradation at the cathode-electrolyte interface, which has traditionally limited commercial lithium-ion batteries to 4.3 volts. By reducing interfacial resistance by approximately 30% after 100 charge cycles, the coated cathodes demonstrated superior performance, including enhanced capacity retention and stable charging speeds at high voltages.
The development has far-reaching implications for multiple industries, particularly electric vehicles (EVs). High-voltage batteries with improved energy density can significantly enhance EV range and performance. The researchers also confirmed the universal applicability of the coating, as it is compatible with various cathode materials, including nickel- and lithium-rich high-voltage batteries. Beyond its technological benefits, the process addresses environmental concerns. Trifluoromethane, a greenhouse gas 10,000 times more harmful than carbon dioxide, is recycled and converted into a stable protective layer for high-voltage cathodes, promoting a circular economy. The study, published in ChemSusChem, highlights this innovation promises to accelerate decarbonization efforts and reshape energy storage technologies worldwide.
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Reference: Aleš Štefančič et al, Converting the CHF3 Greenhouse Gas into Nanometer‐Thick LiF Coating for High‐Voltage Cathode Li‐ion Batteries Materials, ChemSusChem (2024). DOI: 10.1002/cssc.202402057
