New solid-state battery coating nearly doubles volumetric energy density
A solid-state battery research by a team of scientists at University of Texas at Austin has managed to solve the problem of creating lighter cells without the orthodox anode-cathode pair. Previous efforts to get rid of the graphite anode and replace it with a current collector made only of its underlying copper foil resulted in quick material degradation due to the reactivity of the solid electrolyte.
The material scientists experimented with coating materials and found out that lithium-activated tellurium can soak with, or dissolve lithium from the copper foil in a more uniform manner. This prevented the formation of spiky dendrites that can short-circuit, or the appearance of surface irregularities that led to quick battery degradation.
Material scientist David Mitlin explains that the discovery "may provide key missing links for wide-scale commercialization of anode-free and all-solid-state batteries." By dispensing with the graphite anode and using solid sulfide-based electrolyte "you are in effect eliminating half of the battery’s internal material," he added.
The resulting solid-state battery without an electrode pair in the traditional sense is much lighter and more compact than current ternary cells. The lab concept almost doubles the volumetric energy density of traditional batteries, and can store 72% more energy at the same battery pack weight.
These are big numbers, but Mr. Mitlin warns that there is still a long way to go until the anode-less cell makes it to a prototype solid-state battery stage that would be suitable for mass market production and use into the next generation of electric vehicles. A silver lining is that the material scientists managed to apply the new coating with conventional methods that will be suitable for large-scale manufacturing if and when that stage comes.