A team of researchers from Hong Kong has developed an innovative laser printing technology that accelerates the production of lithium-sulfur batteries. The new technology makes it possible to create complex cathode materials in a single step within a fraction of a second, whereas it would normally take several days.
The results of the study, which was led by Mitch Guijun Li, Assistant Professor at the Division of Integrative Systems and Design, Hong Kong University of Science and Technology (HKUST), have been published in the major scientific journal Nature Communications.
Lithium-sulfur batteries are considered a promising alternative to lithium-ion batteries due to the high theoretical energy density of sulfur cathodes. In order to efficiently convert sulfur, these cathodes typically contain active substances, catalysts and conductive components. However, their manufacturing involves many complex stages, each requiring special conditions, which makes mass production time-consuming and expensive.
Aiming to solve this problem, Professor Li’s team has developed a single-step laser printing method that allows them to quickly produce integrated sulfur cathodes. During the process, laser radiation activates special precursors, resulting in the formation of jet particles. They contain hybrid nanotubes based on halloysite (host material), various forms of sulfur (active component) and glucose-derived porous carbon (conductor). The resulting mixture is applied to carbon fabric, forming an integrated sulfur cathode. These laser-printed cathodes have demonstrated excellent characteristics in both coin and pouch lithium-sulfur batteries.
“Traditional production of cathodes and anodes in lithium-ion batteries includes the synthesis of active components, mixing, preparation of suspensions and assembly of electrodes. These processes typically take dozens of hours or even days. Our laser-induced conversion technology combines all these steps into one, taking mere nanoseconds. With a single laser beam, our printing speed can reach 2 cm² per minute. Say, a cathode measuring 75 × 45 mm can be printed in just 20 minutes, and it will be able to power a small screen for several hours when used in a lithium-sulfur cell,” Professor Guijun Li says.
“This has been made possible thanks to an in-depth study of laser-material interactions. Our process is a supercharged thermal action, in which materials are rapidly heated and cooled down, with temperatures reaching thousands of degrees Kelvin. As a result, the original substances decompose and recombine into new structures. In these conditions, we can not only create and combine different materials, but also cause microexplosions that contribute to the formation and movement of the resulting particles,” adds Professor Li’s co-author, former HKUST research fellow Dr. Yang Rongliang.
