Chinese battery manufacturer CATL said it has made significant progress in the development of lithium-metal batteries by improving the electrolyte composition, achieving a high energy density of 500 Wh/kg and extending the battery’s service life to 483 cycles.
The breakthrough, developed at CATL’s 21C Lab and published in the journal Nature Nanotechnology, is considered a step toward commercialising lithium-metal batteries for use in electric vehicles and aviation. Unlike conventional lithium-ion batteries, lithium-metal batteries replace the graphite anode with lithium metal, resulting in reduced weight and improved energy efficiency, though commercialization has been hindered by issues such as dendrite formation and electrolyte degradation.
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CATL researchers focused on the electrolyte’s long-term stability and used new analytical methods to identify the primary cause of battery degradation. “Contrary to previous assumptions, the dominant cause of cell failure is not solvent breakdown, dead lithium accumulation, or solvation environment disruption, but the continuous consumption of the electrolyte salt LiFSI,” the company stated. CATL found that LiFSI was 71% depleted by the end of the battery’s life, suggesting that electrolyte durability is a critical factor for long-term performance.
“We saw a valuable opportunity to bridge the gap between academic research and its practical application in commercial battery cells,” said Ouyang Chuying, co-president of research and development at CATL and deputy director of the 21C Lab. “Our findings underscore that LiFSI salt consumption and, importantly, overall salt concentration is a fundamental determinant of battery longevity.”
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The company invested 18.6 billion yuan ($2.6 billion) in R&D in 2024 and holds more than 43,000 patents worldwide. However, competition in the field remains strong, with LG Energy Solution and South Korea’s KAIST recently announcing progress on lithium-metal batteries using a borate-pyran-based electrolyte.