- CATL has successfully doubled the life of LMB battery cell prototypes with an energy density of 500 Wh/kg.
- The breakthrough came through the use of a new type of lithium salt for the battery electrolyte.
- This brings into focus the importance and potential gains of better electrolytes, which also advances solid-state batteries.
Battery manufacturing juggernaut CATL has announced a breakthrough in lithium metal batteries (LMB), combining increased energy density with a doubling of the usable lifespan observed in previous prototypes. LMBs hold a lot of promise for a wide range of uses, but still have a long way to go before you’ll see them in an electric vehicle.
This new leap is a big step in the right direction, according to CATL, which calls this “a significant step toward commercial viability for applications like electric vehicles and electric aviation.”
There is still a long research and development cycle ahead for LMBs, though, since it remains challenging to find a balance between their energy density and lifespan. If you increase energy density, the batteries wear out quicker, while if you make them last longer, their energy density goes down.
CATL says that the latest prototype had a double lifespan of 483 cycles with an energy density of 500 Wh/kg. For reference, that’s higher than what we expect to get out of solid-state batteries and around twice what current nickel manganese cobalt batteries provide, which typically range from 200 to 300 Wh/kg.
The key to the breakthrough was the use of a different liquid electrolyte than what is typically used. CATL found that the main reason LMB cells failed was linked to the electrolyte being consumed, by as much as 71% by the end of the cell’s life, which accumulated in the cell as “dead lithium.” The company switched to a LiFSI lithium salt, whose higher conductivity and stability helped prolong the higher-energy-density cell’s life.
According to Ouyang Chuying, co-president of Research & Development at CATL, “We saw a valuable opportunity to bridge the gap between academic research and its practical application in commercial battery cells. Our findings underscore that LiFSI salt consumption and, importantly, overall salt concentration [are] a fundamental determinant of battery longevity.”
CATL’s findings suggest that the battery research industry should put more emphasis on the durability of the electrolyte. Another study published in January 2025, drawing from research into medical applications of improved lithium-ion batteries, found that a high-concentration electrolyte is the key to prolonging the life of lithium-metal batteries, which were able to achieve 3,000 charge-discharge cycles while maintaining 80% of their original capacity.
This breakthrough demonstrates that the vast amounts of time and money poured into battery research (CATL alone invested around $2.59 billion into R&D in 2024) do eventually lead to significant breakthroughs.
LMB and solid-state battery research are interconnected as they both share characteristics and can benefit from the same innovations, like CATL’s recent electrolyte-related breakthrough, and both have the same goal of achieving higher energy density, cell safety and a longer usable lifespan, resulting in better batteries for a wide range of uses, especially electric vehicles.
