SK Nexilis said on Monday that its copper foil produced at its factory in Jeongeup has been certified as the longest, widest and thinnest copper foil in South Korea by the Korea Record Institute.
The company can produce copper foil thirty times thinner than the human hair non-stop for four days, it said.
In June, SK Nexilis produced a 4.5 micrometer thin and 1.33 meters wide copper foil 56.5 kilometers long within four days.
The copper foils are used in batteries for electric vehicles.
SK Nexilis previous produced a 6 micrometer thin foil in 2013. It made a 5 micrometer thin foil in 2017. Last year, it succeeded in making a foil 4 micrometers thin within a length of 30 kilometers.
The company recently finished its fourth factory at Jeongeup and now has a production capacity of 34,000 metric tonnes per year for copper foils.
It has started construction of its fifth and sixth factories. When the sixth factory in completed in 2022, it will have an annual production capacity of 52,000 metric tonnes.
The company plans to build its first overseas factories soon. It will decide its location within the year.