Hyundai is pursuing a major step forward in solid-state battery technology with a newly published patent application in the United States, according to a recent report by electrive.com.
The patent covers a method allowing copper to be used inside the cells of solid-state batteries. Traditionally, copper has been avoided in this environment because sulphides are corrosive, forcing manufacturers to rely on nickel or stainless steel.
The patent outlines the use of a protective coating applied over a copper anode current collector. This coating “could deliver significantly better adhesion, letting it stick together longer and have more durability,” while also maintaining capacity over more charge–discharge cycles. The layered design – copper collector, protective coating, anode, sulphide electrolyte, cathode, and terminal collector – allows copper to withstand the electrolyte without degrading. By reintroducing copper, the battery cell could benefit from its high conductivity and lower cost, while improving stability and internal performance in demanding EV applications.
Conventional lithium-ion batteries already rely on copper current collectors to transfer electrons effectively. Solid-state batteries had to rely on more expensive and less conductive materials. This limitation has long posed a cost and performance barrier for the latter.
If successful, the new technology could enable copper’s return as a cost-effective, high-conductivity material for solid-state cells, replacing stainless steel or nickel alloys currently required to resist corrosion. This would not only lower material costs but also enhance efficiency within the cell.
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