Paul van Gerven
1 September 2020

Researchers at Delft University of Technology and Tsinghua University have developed an electrolyte that’s compatible with metallic lithium anodes. This result opens a door to lithium-ion batteries that can store up to ten times more energy compared to current generations of the widely-used storage technology.

Pure lithium metal is the holy grail of lithium-ion battery anodes, but up until now, batteries that feature them don’t live for very long. Because of its high reactivity, lithium continually ‘eats’ the electrolyte, degrading performance. A closely related issue is the formation of so-called dendrites. These ‘spikes’ grow uncontrollably until the battery shorts out.

TU Delft Marnix Wagemaker
Credit: Delft University of Technology

While the newly developed electrolyte also reacts with the lithium, this is actually a good thing because the product of the reaction forms a protective layer on the anode. This stops the detrimental lithium-electrolyte interaction in its tracks. Importantly, the so-called solid-electrolyte interface gladly let’s lithium ions pass through.

It will take a lot more work before superbatteries using the new electrolyte are ready for commercial use, however. To make the most of the discovery, the researchers will now have to tease out the best matching cathode, as well as do lots of optimization. Nonetheless, lead researcher Marnix Wagemaker from TU Delft expects to be able to build a battery that has two or three times the energy density compared to current batteries in the foreseeable future. The cycle lifetime of this battery would probably still need a lot of improvement, though.

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