South Korean vehicle manufacturer Hyundai has found a way to use copper in solid-state sulfide batteries. This discovery could be a major step forward in solid state chemistry. The design holds promise of improved density, safety, and charging speed compared to lithium-ion. However, battery scientists first need to resolve a practical consideration.
What Makes Solid-State Sulfide Batteries Special?
Sulfide is a derivative of sulfur, which corrodes steel, stainless steel and copper on contact. Solid-state batteries normally use polymer electrolytes. Using a sulfide compound instead should produce the benefits we mentioned earlier, were it not for the corrosion.
Copper is a natural anode current collector, on account of its high conductivity. Discovery Alert explains how copper corrosion has been a deal breaker for sulfide battery chemistry. However, Hyundai has now found a way to coat the copper anode, apparently bypassing the corrosion issue.
More About The Novel Protective Layer
Copper is far cheaper than nickel, and 50% more conductive too. This makes it an attractive anode current collector. However, the proximity of a sulfide solid electrolyte soon corrodes the metal, unless there is a buffer between.
The Hyundai buffer layer comprises a vertically-aligned carbon sheet, blended with other materials that work well with lithium-ions. This combination delivers a stable porous structure, that prevents the ions depositing unevenly on the battery anode.
This strategy could lead to commercialization of copper in solid-state sulfide batteries, that weigh less, charge faster, but deliver better heat dispersion. Discovery Alert suggests this makes, “a compelling case for copper’s integration into solid-state battery design”.
Future of Copper in Solid-State Sulfide Batteries
This breakthrough appears to deliver a less-expensive solid-state battery, with a faster charging rate and greater thermal stability. The growing electric vehicle market is hungry for faster-charging primary batteries.
We shall watch this idea with interest, as Hyundai confronts the practical issues relating to mass-manufacture. Who would have thought, a few years ago, that sulfide could have such an important role to play?
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