Japan-based Idemitsu Kosan and NGK Spar Plug as well as Shinshu University and Toyohashi University of Technology are developing materials used in all-solid-state lithium (Li) batteries, according to Japan-based media.
Japan-based energy producer Idemitsu has cooperated with Belgium-based material technology developer Umicore to develop high-efficiency cathode in combination with solid-state electrolyte materials for use in all-solid-state Li batteries, according to Japan-based NHK and Nikan Kogyo Shimbun.
Idemitsu uses in-house petrochemical technology to produce lithium sulfide as a material for making sulfide solid-state electrolytes of all-solid-state Li batteries and owns several patents concerning the electrolyte.
As the compactness of solid-state particles of all-solid-state Li batteries is related to the performance of such batteries, cathode materials are in fusion with solid-state electrolytes to hike operating efficiency for such batteries.
Faculty of Textile Science and Technology under Shinshu University has been in cooperation with Japan-based Tentok Paper and LG Japan Lab to develop a material made from nanofiber and non-woven fabric for use as support of solid-state electrolyte of all-solid-state Li batteries. The ultra-thin film support features high strength and resistance to heat which solves the problems of insufficient strength and low thermal stability occurring to the solid-state electrolytes. All-solid-state Li batteries made up of solid-state electrolytes with such support can be used in electric vehicles to increase endurance running distance.
Toyohashi University has developed the technology that, via high-polarity solvent molecules, can stably solve Li2Sx to shorten the chemical reaction time from 24 hours originally to two minutes and thereby reduce cost and time for producing solid-state electrolytes.
Japan-based ceramic spark plug maker NGK has developed oxide all-solid-state Li batteries for use in aerospace equipment, electric vehicles, medical devices as well as battery materials concerned, and aims to commercialize such batteries in 2025.
Currently, R&D of all-solid-state Li batteries mainly focuses on oxide models and sulfide ones. Sulfide all-solid-state Li batteries have better conductivity of Li ions and thus larger power capacities and higher power output, while oxide models produce almost no toxic substance and are safer.
NGK uses in-house technology of stacking thin ceramic sheets to make oxide all-solid-state Li batteries featuring sizes of 30-110mm, power capacities of 0.5-10Wh, volumetric energy density of 300Wh/liter and wide working temperatures of -30 to 105 degrees Celsius. While the batteries have the highest conductivity of Li ions as compared with other oxide all-solid-state battery models, the corresponding energy density is lower than that of high-quality Li-ion batteries. For the time being, the batteries can be used as back-up power sources for electric vehicles.