Successful development of a new ultra-thin and lightweight lithium-sulfur battery.

Lithium-sulfur batteries have long been valued for their very high energy density relative to weight. However, according to a Science X Dialog post on Tech Xplore, these batteries typically take up 1.5 to 2 times more space than current lithium-ion batteries. This thickness drawback makes lithium-sulfur batteries unsuitable for compact devices where every millimeter of space is crucial.

 

The new design mentioned in the study could open up a different direction by changing a less-noticed component: the binder. This is the 'glue' that holds the electrode materials together inside the battery.

The research team transformed this adhesive into a foam-like substance using protein-based materials. As the foam dries, countless tiny, tubular voids form inside the cathode, much like a sponge with numerous microscopic tunnels.

Next, the cathode is passed through a calendering process, a common step in battery manufacturing, to make the material thinner and denser. Remarkably, despite being compressed intensely, these microscopic 'tunnels' do not collapse. As a result, the cathode is nearly three times thinner than before.

These voids are extremely important because they facilitate the easy movement of ions and matter within the battery during operation. If the cathode is compressed too tightly, these pathways will be constricted, causing a decrease in battery efficiency.

According to the article, this is a major problem that many lithium-sulfur battery designs have encountered. Compressing the cathode to reduce thickness often inadvertently destroys the spatial structure necessary for the battery to function efficiently. With the new foam structure, the cathode layer can act as an internal 'support framework,' allowing the material to be compressed thinly without clogging the pathways.

 

Making batteries thinner only truly makes sense if performance is maintained under heavy load. The article states that the new cathode still retains high capacity even when charging for about 15 minutes, a fast-charging test that easily reveals weaknesses in less stable battery designs.

However, the research has not yet provided complete information on key parameters such as lifespan over multiple charging cycles or details of the manufacturing structure, limiting direct comparisons with other battery technologies. This is a promising direction, but it cannot yet be considered a definitive conclusion.

According to the research team, this method could double battery performance for the same volume – addressing the biggest weakness preventing the widespread adoption of lithium-sulfur batteries. If these results are confirmed, this battery technology could become much more practical for compact devices.

The team also stated they are continuing to optimize for even higher performance, and revealed plans for a spin-off company. There is currently no specific timeline or product, so the next step is to see if this technology can replicate consistent and proven results in real-world production lines.