New lithium battery with high energy density and stability

Solid-state lithium metal batteries have high energy density and stability. Using a novel nitrate-based additive, the team solved the incompatibility problems in battery electrolytes, underscoring the importance of molecular design in developing effective additives for quasi-solid-state electrolytes.

For the first time, Prof. Dr. Francesco Ciucci, Chair of Electrode Design for Electrochemical Energy Systems at the University of Bayreuth, in collaboration with his research partners from China, has succeeded in solving the incompatibility between lithium nitrate and 1,3-dioxolane (DOL) for use in quasi-solid battery electrolytes. They achieved this by integrating a novel nitrate-based additive. This advance has significant implications for solid-state batteries. It enables the development of solid-state lithium metal batteries that are not only extremely safe and durable, but also easy to manufacture. In addition, this process maintains existing manufacturing methods for conventional liquid batteries.

"At the same time, the solid-state nature of the batteries ensures a high level of safety, while their production remains simple," explains Prof. Ciucci. "We have demonstrated the universality of the approach by fabricating different types of lithium metal batteries. In particular, the fabricated pouch Li-S cell exhibits better performance than previously documented pouch Li-S cells." In a study published in the journal Energy & Environmental Science, Prof. Ciucci's research team introduced a new additive, triethylene glycol dinitrate, specifically designed for the polymerization of DOL. The research team showed that the formation of a nitrogen-rich solid electrolyte interlayer associated with polymerization suppresses harmful parasitic reactions and increases battery efficiency.

Based on the study results, several battery cells were developed. Among them, a button cell could be stably charged and discharged more than 2000 times at laboratory scale. Also, a 1.7 Ah Li-S pouch cell with a high energy density of 304 Wh kg-1 and stable cycles was also produced. Prof. Ciucci confirms, "This study highlights the importance of molecular structure design in the development of effective additives for quasi-solid-state electrolytes. It represents a significant advance in the practical feasibility of using poly-DOL-based quasi-solid-state electrolytes in lithium metal batteries."