Oak Ridge National Laboratory (ORNL) researchers have developed a new pressing method, that produces a more uniform solid electrolyte than the traditionally processed material with more voids. The material can be integrated into a battery system for improved stability and rate performance.

When a solid-state battery charges or operates, ions move between electrodes through the solid electrolyte between them. The new method for pressing the solid electrolyte practically eliminates tiny air pockets that block ion flow, so the battery charges twice as fast.

An open-access paper on the method is published in ACS Energy Letters.

a) Schematic diagram showing the principle of controlling grain-level microstructure for antiperovskite materials. The pellets shown in the inset are 12.5 mm in diameter. Conventional uniaxial processing leads to opaque, white pellets, while the developed approach leads to a translucent pellet. (b) X-ray tomography cross sections of conventional and our developed protocol-processed antiperovskite materials. We evaluated the porosity of the conventional pellet at 12%, while no discernible microstructural features could be observed in the pellet processed using our new process. (c) X-ray diffraction patterns of the synthesized powder and the pellets processed with both approaches. Dixit et al.

ORNL lead researcher Marm Dixit said the approach involved heating the press after spreading the electrolyte on it, then letting the electrolyte cool under pressure. The resulting material was almost 1,000 times more conductive.

It’s the same material—you’re just changing how you make it, while improving the battery performance on a number of fronts.

—Marm Dixit

These results demonstrate a pathway for processing solid electrolytes at an industrial scale while providing unprecedented control over their internal structure for a more reliable battery.

Resources

• Marm Dixit, Nitin Muralidharan, Anuj Bisht, Charl J. Jafta, Christopher T. Nelson, Ruhul Amin, Rachid Essehli, Mahalingam Balasubramanian, and Ilias Belharouak (2023) “Tailoring of the Anti-Perovskite Solid Electrolytes at the Grain-Scale” ACS Energy Letters 8 (5), 2356-2364 doi: 10.1021/acsenergylett.3c00265