High Level Similarity between Solid-state and Liquid-state Electrolyte used in Batteries, finds study

Research undertaken at the McKelvey School of Engineering is the first to show that a solid-state electrolyte has a high degree of similarity to liquid electrolytes. This is promising for designing more efficient and safer solid-state batteries driven by reliable mechanistic knowledge.

“The findings exhibit striking similarities between solid and liquid electrolytes, and this allows to borrow some ideas from much-used liquid electrolytes in the design of solid electrolytes,” stated one of the research associates. Prior to this work, solid electrolytes, at least ceramic ones studied in the research, are considered distinctly different from liquid electrolytes.

Importantly, batteries are used to power so much in our lives, so finding new improvements will have a dramatic societal impact, stated the associate.

The development of a full solid-state battery is a promising route to this. The electrolyte in the center of the battery is a key component, which allows ion movement between the electrodes. In this arrangement, a liquid electrolyte is replaced with a solid and attached to a metal electrode. This has dual advantages of boosting the amount of energy that is stored and resulting in potentially safer batteries.

However, the increasing number of reports about solid-state batteries throw light on a key roadblock, known as critical current density (CCD). This is the tipping point beyond which small tree-like structures called dendrites develop, resulting in battery failure. The CCDs are relatively low, which prevents fast charging and holds back further development of solid-state batteries.

Meanwhile, the CCD of solid-state electrolytes is clueless. Researchers are working to uncover the reason for its existence, its true physics, and how it changes under different operating conditions, stated the principal investigator of the project and corresponding author of the paper published in ACS Energy Letters.