Chinese researchers develop copper foil combining strength, conductivity, thermal stability

SHENYANG, April 17 (Xinhua) -- Chinese researchers have developed a new type of copper foil that overcomes a long-standing trade-off among strength, electrical conductivity and thermal stability, offering a promising material for advanced electronics and next-generation energy storage systems.

The innovative copper foil was created by a team led by Lu Lei at the Institute of Metal Research, Chinese Academy of Sciences. The findings were published in Science on Friday.

Copper foil is a key component in integrated circuits and lithium-ion batteries. However, pure copper is soft and weak, making it unsuitable for applications requiring high load-bearing capacity or heat resistance. Adding other elements can improve strength and thermal stability, but that often reduces electrical conductivity.

The breakthrough lies in a new microstructural design called "gradient nano-domain architecture". Using an industrially scalable electrodeposition process, the team added trace amounts of organic additives to produce a 10-micrometer-thick copper foil containing high-density super-nano domains, each only about three nanometers in size.

These tiny copper domains act like rivets embedded inside the copper. They hinder the movement of copper grains, thereby increasing strength and thermal stability while maintaining high copper purity. As a result, the material does not block electron flow and maintains good conductivity.

The new copper foil achieved a tensile strength of approximately 900 megapascals, far exceeding that of conventional copper foil. Its electrical conductivity reached 90 percent of pure copper, roughly three times that of other copper alloys with similar strength levels. The material also showed exceptional thermal stability.

The team added that the research provides a new design pathway for developing high-performance metallic materials. More importantly, the gradient nano-domain copper foil can already be produced continuously under industrial conditions, thereby supporting high-end applications in the electronics and new energy industries.  ■