Super-nano domains enable strength-conductivity synergy in copper foils

The development of copper foils that simultaneously exhibit ultrahigh strength, high electrical conductivity, and thermal stability remains a major challenge for advanced electronics and energy storage systems. We report a 10-micrometer-thick copper foil featuring nanoscale grains and periodically distributed gradient super-nano domains (approximately 3 nanometers in size) throughout its thickness that was produced by an industrially scalable electrodeposition process. This copper foil demonstrates a combination of approximately 900-megapascal tensile strength, 90% standard electrical conductivity, and exceptional thermal stability. These superior properties originate from a dual strengthening-stabilization mechanism in which the periodically distributed super-nano domains both enhance strength and stabilize grain boundaries. This strategy not only advances copper foil technology but also provides a general design pathway for developing other scalable, high-performance metallic materials.