Domestic researchers have developed technology to accelerate the commercialization of 'lithium-sulfur batteries,' a key technology that is recognized as a major player in the move toward lightweight and long-lasting batteries and urban air mobility (UAM).
Researcher Park Jun-woo, head of the Next Generation Battery Research Center at the Korea Electrotechnology Research Institute (KERI), noted on the 20th that the research team has succeeded in overcoming challenges that hindered the commercialization of next-generation lithium-sulfur batteries and has even produced large-area, high-capacity prototypes. The results of this study were published in the international journal 'Advanced Science' in December of last year.
Lithium-sulfur batteries, composed of sulfur as the cathode and lithium metal as the anode, have a theoretical energy density more than eight times that of lithium-ion batteries, giving them significant potential. They are inexpensive and environmentally friendly because they use sulfur, which is abundant, instead of costly rare earth elements. However, lithium-sulfur batteries generate an intermediate substance called 'lithium polysulfides' during the charging and discharging process, which moves between the cathode and anode, causing unnecessary chemical reactions that reduce the lifespan and performance of the battery.
The research team addressed the issues of lithium-sulfur batteries by utilizing single-walled carbon nanotubes (SWCNTs) with oxygen functional groups. SWCNTs are stronger than steel and have electrical conductivity comparable to copper, making them a promising new material. The oxygen functional groups help distribute SWCNTs well within the battery. The SWCNTs, combined with oxygen functional groups, stably encase electrodes that can expand during charging and discharging, effectively controlling the leaching and diffusion of lithium polysulfides, and significantly reducing the loss of sulfur, the active material.
The highly flexible SWCNTs and the hydrophilic oxygen functional groups enable the creation of uniform and smooth surfaces during electrode fabrication, allowing for the design of large-area, high-capacity batteries. The research team was able to produce a flexible thick electrode measuring 50 mm in width and 60 mm in length, stacking them carefully to create a prototype of a pouch-type lithium-sulfur battery with a capacity of 1000 mAh (1 Ah). The prototype maintained more than 85% of its capacity after 100 cycles of charging and discharging.
Park Jun-woo stated, "Through the combination of SWCNTs and oxygen functional groups, we have not only overcome the biggest challenges of lithium-sulfur batteries but also achieved the design of large-area, high-capacity flexible electrodes and prototype production. This lays a foundational framework for practical applications in real industry settings, marking a significant achievement that enhances the commercialization potential of next-generation lithium-sulfur batteries."
The research achievements have also led to the completion of domestic patent applications. The Korea Electrotechnology Research Institute anticipates that these achievements will attract interest from corporations in various fields such as urban air mobility, aerospace, energy storage systems (ESS), and electric vehicles, and plans to identify demand companies to promote technology transfer.
References
Advanced Science (2024), DOI: https://doi.org/10.1002/advs.202406536