In China, they created a lithium-sulfur battery that is resistant to cuts and deformations – it works even if damaged

A group of Chinese scientists has presented a prototype lithium-sulfur battery that is resistant to damage. The goal of the work was to create a safer alternative to lithium-ion batteries, which are prone to fire when damaged. The new battery showed absolute reliability, continuing to work even after it was bent in half and then half was cut off.

Bent. Image source: ACS Energy Letters

For lithium-sulfur batteries, the low number of charge and discharge cycles remains a big problem, which hinders their commercialization. Scientists from the University of Electronic Science and Technology of China, the China Institute of Advanced Energy Storage Technology at Tianmu Lake, the Chinese Academy of Sciences and the University of British Columbia in Canada are involved in finding compounds and solutions that could improve the cycling of these promising batteries.

Transition metal sulfides were used as the basis for the cathodes of promising Li-S batteries. The main problem with such compounds is that upon high heating, polysulfides began to actively move through the electrolyte, which led to swelling of the batteries and a decrease in electrochemical reactions. Carbonate-based electrolytes partly solved this problem, but they also created another problem – they caused the appearance of sediment (passivation) on the battery electrodes, which quickly reduced the number of battery cycles.

To protect the iron sulfide (FeS2) cathode and high-metal lithium anode from precipitation, the researchers used three different electrode coatings: polyacrylic acid (PAA), polyacrylamide (PAM), and polyethylene oxide (PEO). All these compounds had a chelate effect (they bound “bad” ions), which prevented the formation of sediment on the electrodes. Experiments showed that coating the electrodes with polyacrylic acid gave the greatest effect.

And they cut it off…

After 300 recharge cycles, the pouch battery prototype retained 72% of its original capacity, showing no decline after the first 100 cycles. Bending the battery in half and then cutting off half of it did not cause the battery to fail and explode, as would happen with a conventional lithium-ion battery, proving the future batteries’ absolute safety. However, there is still a lot of work to be done on them before moving on to commercial production. Perhaps things are better with lithium-sulfur batteries from American developers, who have already established their limited mass production. But that’s another story.