Foiled Again! Sterne Kessler Secures Fourth IPR Denial for SK nexilis

Washington, D.C. (May 21, 2025) – Sterne, Kessler, Goldstein & Fox secured a 59-page denial on the merits of a PTAB inter partes review petition of U.S. Patent No. 9,457,541 on behalf of patent owner SK nexilis. SK nexilis has asserted the ’541 patent and four other patents against Solus Advanced Materials in a co-pending district court patent infringement lawsuit. Solus filed IPR petitions against all five patents, four of which have been denied. One has been instituted, but is pending a Director Review request. The patents relate to electrolytic copper foil for secondary batteries, such as those used in electric vehicles. SK nexilis has long been a leader in the battery copper foil industry, with significant investment in the research and development of battery copper foil products. The institution denial decision can be reviewed here.

The Sterne Kessler team representing SK nexilis included Directors Jennifer Meyer Chagnon, Jason A. Fitzsimmons, Charles D. Hammond, Ian Soule, Daniel E. Yonan, and Michael D. Specht. The present PTAB case is IPR2025-00005, Solus Advanced Materials Co., LTD v. SK nexilis Co., Ltd.