Increasing Lithium-Ion Conductivity Enables Operation at Room Temperature
Ensuring High-Speed Charging Performance
SK On has succeeded in jointly developing a polymer electrolyte for lithium metal batteries that can operate at room temperature.
On the 16th, SK On announced that it had developed a new polymer electrolyte called 'SIPE (single-ion conducting polymer electrolyte)' in collaboration with Professor Hardy Carney's research team at the University of Texas, USA.
Polymer electrolytes are attracting attention as next-generation solid battery materials due to their low cost and ease of manufacturing. However, compared to oxide-based and sulfide-based electrolytes, their ionic conductivity is low, limiting operation to high temperatures of 70~80°C, which is one of the challenges to overcome.
SIPE addresses this by improving ionic conductivity and lithium ion transport number. It increased room temperature ionic conductivity by about 10 times compared to conventional polymer electrolytes and nearly quintupled the lithium ion transport number.
Experimental results showed that batteries using SIPE maintained 77% of their discharge capacity even during high-speed charging and discharging compared to low-speed charging and discharging. Solid electrolytes typically exhibit significant discharge capacity degradation during fast charging due to low ionic conductivity, but this was minimized.
By enhancing the interfacial stability of the solid electrolyte, dendrite formation was also suppressed. Lithium metal batteries use metallic lithium instead of graphite as the anode, significantly increasing energy density, but solving the dendrite issue is essential for commercialization.
Additionally, SIPE exhibits excellent thermal safety, withstanding high temperatures above 250°C.
SK On is developing two types of all-solid-state batteries: polymer-oxide composites and sulfide-based systems. The goal is to produce pilot prototypes in 2025 and 2026, respectively, and commercial prototypes in 2028 and 2029.
Since 2020, SK On has been jointly developing solid electrolytes for lithium metal batteries with the research team of Professor Goodenough at the University of Texas, a Nobel Prize laureate in Chemistry. After Professor Goodenough passed away in June last year, his prot?g? Professor Carney has been leading the research team.
Kim Taekyung, head of SK On's Next Generation Battery Center, said, "Based on this research achievement, we expect to accelerate the development of solid batteries applying polymer electrolytes. Leveraging the competitiveness of new material technologies, we will secure growth opportunities in the next-generation battery field in the future."
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