Graphene foil promises to thwart thermal runaway in lithium-ion batteries

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The safety and performance of lithium-ion batteries could be improved following the development of a technique for producing large-scale graphene current collectors by researchers in Wales and China.

Researchers at Swansea University, in collaboration with Wuhan University of Technology, Shenzhen University, have developed a pioneering technique for producing large-scale graphene current collectors
Researchers at Swansea University, in collaboration with Wuhan University of Technology, Shenzhen University, have developed a pioneering technique for producing large-scale graphene current collectors - Swansea University

Published in Nature Chemical Engineering, the study - by a team at Swansea University in collaboration with Wuhan University of Technology and Shenzhen University - details the first successful protocol for fabricating defect-free graphene foils on a commercial scale.

The foils are fabricated through a continuous thermal pressing process and are said to offer thermal conductivity up to 1,400.8 W m–1 K–1, which is nearly ten times higher than traditional copper and aluminium current collectors used in LIBs.

In a statement, Dr Rui Tan, co-lead author from Swansea University, said: “This is a significant step forward for battery technology. Our method allows for the production of graphene current collectors at a scale and quality that can be readily integrated into commercial battery manufacturing. This not only improves battery safety by efficiently managing heat but also enhances energy density and longevity.”

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High-energy LIBs can be subject to thermal runaway, a scenario where excessive heat leads to battery failure, often resulting in fires or explosions. These graphene current collectors are designed to mitigate this risk by dissipating heat and preventing the exothermic reactions that lead to thermal runaway.

“Our dense, aligned graphene structure provides a robust barrier against the formation of flammable gases and prevents oxygen from permeating the battery cells, which is crucial for avoiding catastrophic failures,” said Dr Jinlong Yang, co-lead author from Shenzhen University.

The scalable process is capable of producing graphene foils in lengths ranging from meters to kilometres. In a demonstration of its potential, the researchers produced a 200m long graphene foil with a thickness of 17μm. This foil retained high electrical conductivity even after being bent over 100,000 times, extending its utility for use in flexible electronics and other advanced applications.

This new approach also allows for the production of graphene foils with customisable thicknesses, which could lead to even more efficient and safer batteries.

According to Swansea, this innovation could have wide-reaching implications for the future of energy storage, particularly in electric vehicles and renewable energy systems, where safety and efficiency are paramount.

The international team is refining the process, with efforts to reduce the thickness of the graphene foils and further enhance their mechanical properties. They are looking also at using this new material beyond Li-ion batteries, such as in redox flow batteries and sodium-ion batteries.

graphene current collector