South Korean battery maker SK On said it has completed a pilot plant for solid-state batteries at its research centre in Daejeon, aiming to commercialise sulphide-based cells by 2029, a year earlier than initially planned.
The facility will focus primarily on sulphide-based solid-state batteries, while some lines will also be configured for lithium-metal anode variants. SK On is developing two types of solid-state technology — polymer-oxide composite batteries targeted for commercialisation by 2028 and sulphide-based batteries the following year. The new plant was built with technical support from U.S. partner Solid Power.
SK On acquired licences from Solid Power in early 2024 to use its cell technology for research and prototype development in South Korea. The Daejeon plant will produce test cells to gather performance and quality data ahead of mass production. The company has set energy density targets of 800 Wh/l in the medium term and 1,000 Wh/l in the longer term.
Solid Power, which also partners with BMW and Ford, developed a sulphide-based solid electrolyte material and disclosed its solid-state platform in 2021. The company uses conventional NMC cathodes, allowing existing production processes to be retained. With a silicon anode and solid electrolyte, Solid Power’s cells can reach an energy density of 390 Wh/kg, rising to 440 Wh/kg with a lithium-metal anode and NCM-811 cathode.
In recent updates, SK On has reported progress on solid polymer electrolytes operable at room temperature, a light energy-based method for solid electrolyte production, and improved cycle life of sulphide-based batteries using lithium-metal anodes.