Chinese battery giant CATL has announced a major breakthrough in lithium-metal battery (LMB) technology through what it calls “quantitative mapping,” marking a new milestone in its electrolyte strategy. According to the company, this research—published in Nature Nanotechnology—paves the way for high energy density LMBs with significantly extended lifespan, tackling one of the biggest longstanding challenges in the field.
The company revealed that its optimized battery prototype has achieved a cycle life of 483 cycles and can be integrated into modern designs capable of delivering an energy density of over 500 Wh/kg. “This represents a significant step towards making these batteries commercially viable for applications such as electric vehicles and electric aviation,” CATL stated in its press release.
LMBs are considered next-generation battery systems due to their inherently high energy density, particularly attractive for premium use cases like electric cars, long-range electric commercial vehicles, and electric aircraft. However, CATL acknowledged that LMBs have traditionally struggled to balance energy density with cycle life, often forcing trade-offs between the two.
Until now, most research in the field has focused on enhancing cell performance by optimizing solvation structures and the interfaces between solid electrolytes and other battery components. But as CATL explains, these efforts often compromised battery longevity, and none yielded commercially viable solutions. Moreover, the challenge of accurately tracking the consumption of active lithium and electrolyte components during battery operation has hampered a deeper understanding of LMB failure mechanisms.
Diluent Breaks the Deadlock
To overcome this limitation, CATL’s research and development team developed and refined a suite of analytical techniques that allows them to monitor the consumption of active lithium and each electrolyte component throughout the battery’s lifecycle. This approach effectively turned the “black box” of LMB chemistry into a “white box,” exposing the critical depletion pathways that lead to cell failure.
Contrary to previous assumptions, the team discovered that the primary reason for cell degradation was not solvent breakdown, the buildup of inactive lithium, or solvation disruption. Instead, it was the continuous depletion of the LiFSI electrolyte salt—71% of which is consumed by the end of the battery’s life. “These findings highlight the need for the industry to look beyond Coulombic efficiency (CE)—long seen as the key metric for LMBs—and to also consider electrolyte retention as a vital factor for sustainable performance,” CATL explained.
Building on these insights, the company refined its electrolyte formula by introducing a diluent with lower molecular weight. This innovation increased the salt-to-solvent ratio, boosted ionic conductivity, and reduced viscosity—all without increasing the total electrolyte mass. While the updated LMB prototype maintained the same CE as its predecessor, it doubled its lifespan to 483 cycles and reached an energy density exceeding 500 Wh/kg. According to CATL, this advancement marks a paradigm shift toward the development of batteries that are both energy-dense and durable.
Same Weight, Twice the Energy
To put this into perspective, today’s commonly used NMC batteries have an energy density of around 250 Wh/kg—half the performance of CATL’s new LMB prototype. LFP batteries, which are increasingly adopted by companies like Tesla, typically offer less than 200 Wh/kg. Even solid-state batteries, widely regarded as a future solution, haven’t yet achieved such impressive figures.
For a battery pack with 100 kWh capacity, a conventional system would require 400 kilograms of battery material. In contrast, an LMB battery could achieve the same capacity with just 200 kilograms. At the same weight, it could store 200 kWh of energy. With the cycle life reported by CATL, this would allow a total energy throughput of nearly 100,000 kWh—enough to power an electric vehicle for about 500,000 kilometers.
This leap in performance could set a new benchmark for next-generation electric mobility and aircraft applications, potentially transforming the landscape of energy storage technologies.
