A research group lead by Mitch LI Guijun, PhD, assistant professor at the Hong Kong University of Science and Technology (HKUST), has designed a groundbreaking single-step printing technique for cathodes to accelerate the manufacturing of lithium-sulphur (Li-S) batteries.
Lithium-sulphur batteries are a promising chemistry as a sustainable and cost-efficient next generation alternative to conventional lithium-ion batteries. However, there are still some obstacles on the way to commercial success. Production of sulphur cathodes, which theoretically can offer a five times higher energy density, is technically complex.
To enable efficient sulphur conversion, these cathodes typically comprise active materials, host materials (or catalysts), and conductive agents. Instead of using a multi-step process that demands precise temperature control and significant labour, making it costly and inefficient for large-scale manufacturing, the researchers have invented a method, where they use a high-speed laser-induced conversion process that integrates multiple complex steps.
In this high-throughput laser-pulse process, the precursor donor is rapidly activated, generating jetting particles that simultaneously produce halloysite nanotubes (host), sulphur species (active), and glucose-derived porous carbon (conductive). The mixture is directly printed onto a carbon fabric substrate, creating a fully integrated cathode.
Yang Rongliang, PhD, a former postdoctoral fellow at the university and first author of the study said that this ultra-concentrated thermal process not only enables the formation and combination of materials with different natures but also drives the concomitant micro-explosions that facilitate the jetting and transferring of forming particles.
“Our newly developed laser-induced conversion technology offers a way to combine these processes into a single step at nanosecond speeds,” assistant professor Li highlights. “The printing speed can achieve about 2 cm²/minute using only a single beam laser.” The team was able to print a 75 × 45 mm² sulphur cathode in just 20 minutes.
Photo: Assistant Professor Mitch Li Guijun, PhD. Credit: Hong Kong University of Science and Technology
