Abstract
This publication discusses a rapid, real-time, scalable and form-factor agnostic diagnostic of lithium-ion battery wetting. By monitoring gas emission from a chemical reaction that is a surrogate for liquid electrolyte contact with electrode material, the extent of wetting can be inferred as a function of time. For instance, lithium carbonate spontaneously reacts with lithium hexafluorophosphate to produce carbon dioxide gas. Lithium carbonate is a surface-segregated species on cathode active material that is left as a byproduct of synthesis. It coats and penetrates the secondary particle aggregate structure of cathode material. Lithium hexafluorophosphate is the state of the art, primary salt that carries lithium ions in the battery. Thus, both materials necessary for this diagnostic are naturally present in the cell. Before electrochemical cycling, carbon dioxide is produced if these two materials establish contact. Thus, emission of carbon dioxide is directly related to electrolyte penetration into porous cathode particles. Further, by combining gas measurement during wetting with prior knowledge of the total amount of accessible lithium carbonate on the cathode, one can know how much gas will be emitted once all cathode has been contacted with electrolyte (i.e., wetting is complete). The total amount of accessible lithium carbonate is characterized for a representative batch of cathode powder via a soluble lithium/acid-titration measurement (e.g., wash cathode powder in water, titrate the supernatant to count soluble lithium carbonate and lithium hydroxide).
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Recommended Citation
Anonymous, "Carbon Dioxide Battery Electrode Wetting Diagnostic", Technical Disclosure Commons, (February 02, 2025)
https://www.tdcommons.org/dpubs_series/7793