Nature Communications, Published online: 10 June 2026; doi:10.1038/s41467-026-74193-8 This study showcases a breakthrough in the field of lithium-ion battery (LIB) metrology, demonstrating over a two-orders-of-magnitude improvement in precision for noncontact thickness measurements, and achieving nanometre-precision using frequency-comb referenced terahertz (THz) interferometry.