New ‘regenerative’ material could lead to battery revolution

A group of scientists from the University of California, San Diego (USA) has found a self-healing material that will help create improved batteries from sulfur and lithium. They published an article about the study in the journal Nature.

Physicists have long been trying to create solid-state lithium-sulfur batteries because they represent a theoretically better alternative to the current lithium-ion batteries that currently power smartphones and other technologies, thanks to greater energy storage and lower costs. It would be very beneficial for electric vehicles if they could double the range without increasing weight or size.

These batteries consist of a solid electrolyte, an anode made of lithium metal, and a cathode made of sulfur. It turns out that the main problem is the cathodes (electrodes of negative polarity) – sulfur does not conduct electrons well, so it can expand and contract during charging and therefore be damaged during operation. But now scientists have made a new material for cathode electrodes in the form of sulfur and iodine crystals. Iodine increases the conductivity of the cathode by 100 billion times.

“We are very excited about the discovery of this new material. The sharp increase in the electrical conductivity of sulfur is unexpected and very interesting from a scientific perspective,” said Ping Liu, professor of nanoengineering and director of the Center for Sustainable Energy. Energy at the University of California, San Diego, reports the EurekAlert website.

What’s more, the new crystal material has a melting point (65 degrees Celsius (149 Fahrenheit)) low enough to make a cup of coffee hotter. This means that the cathode can be easily melted after charging and damaged parts can be repaired after a few cycles. This is an important feature that will make your lithium sulfur battery last much longer.

Nanoengineering professor Shue Ping Ong, one of the authors of the study, said the discovery could help bring lithium-sulfur batteries to the commercial market. Iodine breaks down the intermolecular bonds that hold sulfur molecules together enough to lower the melting point to the optimum level (above room temperature, but low enough for uniform melting).

“The low melting point of our new cathode material makes it possible to repair the interfaces, a long-sought solution for these batteries,” said Jianbin Zhou, one of the authors of the study. “This new material is a promising solution for future high energy.” density solid state batteries.

To test the effectiveness of the new cathode material, the researchers created a test battery and subjected it to repeated charge and discharge cycles. The battery remained stable for more than 400 cycles while retaining 87 percent of its capacity.

“A battery’s ability to self-heal by simply increasing the temperature could significantly extend the overall lifespan of the battery and create a potential path to real-world applications for solid-state batteries,” said lead scientist Christopher Brooks, co-author of the study. at the Honda Research Institute in the USA.

The team is working to further develop solid-state lithium-sulfur battery technology by improving the cell design and expanding its format.

“While much remains to be done to create a viable solid-state battery, our work represents an important step. This work was made possible thanks to close collaboration between our teams at UC San Diego and our research partners in national laboratories, academia, and industry,” Ping Liu added.

We have previously written about when smartphones might get a new type of battery. For example, Betavolt Technology, a startup in China, has introduced a new nuclear battery that can power a smartphone for 50 years.