Chinese researchers have developed an ultra-thin copper foil material of ultrahigh strength, high conductivity and high thermal stability, paving the way for next-generation batteries and integrated circuits.

Copper foil serves both as a channel for electric current and as a conductor of heat. For decades, improving strength has come at the expense of conductivity, while better conductivity often weakens thermal stability.

Now, researchers say they've cracked that trade-off. The material is a 10-micrometer-thick copper foil featuring nanoscale grains and periodically distributed gradient super-nano domains of approximately 3 nanometers in size throughout its thickness. It can be produced through an industrially scalable electrodeposition process.

In terms of strength, conventional industrial copper foil typically has a tensile strength of around 300 to 600 megapascals. The newly developed material reaches about 900 megapascals, roughly twice as strong.

By decoupling strength from conductivity, the new material retains electrical conductivity at 90% of high-purity copper. Compared with traditional copper alloys of similar strength, its conductivity is roughly twice as high.

It also demonstrates strong thermal stability. While many high-strength materials tend to degrade within days, the new copper foil shows no decline after six months of storage under normal conditions, making it well suited for electronic devices and batteries that require long-term stability.

According to the researchers, these properties stem from a dual stabilization-strengthening mechanism, in which periodically distributed super-nano domains simultaneously enhance strength and stabilize grain boundaries.

With its demonstrated industrial scalability, the material is expected to support next-generation upgrades in smartphones, artificial intelligence (AI) chips and electric vehicles.