Although most humans only relate room temperature with personal comfort, room temperature is significant for scientists attempting to develop specific material phases.
All-solid-state lithium battery. Osaka Metropolitan University scientists crystalized Li3PS4, a solid electrolyte material, via rapid heating, enabling the stabilization of its high-temperature phase with exceptional ionic conductivity even at room temperature. Image Credit: Akitoshi Hayashi, Osaka Metropolitan University
Osaka Metropolitan University researchers have accomplished an unparalleled stabilization of the Li3PS4’s high-temperature phase—a crucial material for all-solid-state batteries—thereby achieving outstanding ionic conductivity at room temperature. This discovery gets people one step ahead in the realization of all-solid-state batteries and the implementation of this technology in a wide array of applications, along with electric vehicles.
All-solid-state batteries are predicted to be put to practical application as next-generation energy storage devices that combine high grades of safety and improved energy density, thus realizing a sustainable society. All-solid-state lithium batteries function by enabling the mobility of lithium ions via a solid electrolyte. Nevertheless, as ions could not mobilize freely within solids, developing solid electrolytes with high ion conductivity that, such as liquid electrolytes, facilitate the quick transfer of lithium ions, is imperative.
A study team headed by Professor Akitoshi Hayashi and Associate Professor Atsushi Sakuda of the Graduate School of Engineering at Osaka Metropolitan University was efficient in stabilizing the high-temperature phase of Li3PS4 (α-Li3PS4) for the first time. At room temperature, this shows high ion conductivity through quick heating to crystallize Li3PS4 at 400 °C min−1. Because Li3PS4 is a potential solid electrolyte, this achievement has the potential to develop materials for all-solid-state batteries that exhibit greater performance.
Li3PS4 showcases varied crystal structures depending on temperature variations. The high-temperature phase is generally recognized for its superior ionic conductivity; however, the challenge has been to stabilize this phase at room temperature. We finally accomplished it by focusing on the heating rate during crystallization. This is the culmination of nearly 20 years dedicated to the development of all-solid-state battery materials.
Akitoshi Hayashi, Professor, Graduate School of Engineering, Osaka Metropolitan University
The research was published in Journal of the American Chemical Society.
Funding
This research was funded by the Japan Science and Technology Agency ALCA-SPRING project (grant number JPMJAL1301) and Japan Society for the Promotion of Science KAKENHI grants (grant numbers JP18H05255 and JP19H05816).
Journal Reference:
Kimura, T., et al. (2023). Stabilizing High-Temperature α-Li3PS4 by Rapidly Heating the Glass. Journal of the American Chemical Society. doi.org/10.1021/jacs.3c03827.