Electrive writes that the experts developed the new sulfide solid-state electrolytes based on their previous research, where they used polymers (plastics). Through the latest research, they were able to determine how thin they could make the film thinner, while maintaining the optimal ionic conduction and the structural strength.

Current-generation solid electrolytes use a plastic-based binder to conduct the ions, but this process lowers the conductivity compared to liquid electrolytes. This means that engineers have to use liquid electrolytes even for a polymer-based electrolyte, resulting in a semi-solid battery, which comes with a drawback in terms of safety, as the solid electrolyte is more flammable.

The team at ORNL explored replacing the liquid electrolyte with a sulfide electrolyte for batteries, which has a comparable ionic conductivity to the traditional material.

Additionally, optimizing the weight of the polymer binder is crucial to achieve a good energy density and to support the battery's stability, while making sure that it's not too thin that it compromises its structural integrity.

Guang Yang from ORNL said that "we want to minimize the polymer binder because it does not conduct ions. The binder’s only function is to lock the electrolyte particles into the film."

Using these discoveries, they can now start developing more advanced batteries, which can achieve double the energy density of current-generation cells to "at least 500 watt-hours per kilogram".