Forget solid-state batteries, another major electric car battery breakthrough could leave BMW, Mercedes-Benz, MG, Chery, Nissan, Toyota and Stellantis reeling

Chinese battery giant CATL has announced a major battery breakthrough in its lithium metal battery (LMB) technology that surpasses the theoretical energy efficiency of some solid-state batteries.

It is still in prototype phase, but CATL, which supplies the batteries that power electric cars from Tesla, Toyota, Volkswagen, BMW, Hyundai and more, claims to have developed a LMB battery with an optimised energy efficiency of 500kWh/kg maintained over 483 charging cycles.

That level of energy efficiency far exceeds anything currently available on the mainstream EV market, with most EV batteries currently residing between a peak of 150Wh/kg to 250Wh/kg over an approximate lifecyle of up to 1000 charging cycles.

Better yet, it exceeds significant developments in solid-state battery technology, which is often touted as a silver bullet for EV technology due to its high energy density and long-range driving potential.

BMW, one of the leaders in solid-state battery technology, has been targeting an efficiency of between 390Wh/kg and 550Wh/kg in its partnership with Solid Power, though it is yet to claim an achieved figure, despite recently testing one fitted to a BMW i7 prototype.

Stellantis, which is also working on solid-state batteries with Factorial Energy, claims to have achieved an energy density of 375Wh/kg over 600 charging cycles on its solid-state batteries, which it aims to roll out on a demonstration fleet by next year.

Unlike solid-state batteries, which use a solid electrolyte, CATL's LMB batteries use a liquid electrolyte, which could theoretically present fewer challenges in the development and manufacturing processes.

CATL said it has maximised energy efficiency on its LMB batteries through quantitative mapping. In other words, by exploring more intensively why its LMB batteries would start to lose efficiency.

2025 BMW i7 prototype

It was found that by tweaking the battery’s electrolyte, it could make the LiFSI salt – a key component used to improve battery performance – last longer. By doing so, it doubled the number of charging cycles in its previous prototype to nearly 500.

CATL is heralding the development as an exciting step forward for improving battery technologies in the commercial EV and aviation space, and one that could face fewer hurdles in upscaling the technology as solid-state batteries do.

The company is the biggest battery manufacturer in the world and currently holds a 37 per cent market share of global lithium-ion battery supply.