DETECTION OF DEFECTS IN SOLID-POLYMER COATINGS USING REDUCTION-OXIDATION PROBES

摘要

Electrochemical methods for probing solid polymer electrolyte surface coatings on electrically conducting, active, three-dimensional electrode materials for use in lithium-ion batteries, to quantitatively determine the conformity, uniformity, and the presence of pinholes, and/or other defects in coatings, without requiring the detachment of the coating from the electrode or otherwise inducing damage to the coating, are described. Coated electrodes are submersed in an electrolyte solution containing a redox-active probe species which does not induce electrochemical damage to either the working electrode or the solid polymer electrolyte surface coating. For coated Cu2Sb working electrodes, molecules including a water-soluble redox active viologen moiety have been found to be effective. The current as a function of the applied potential for an uncoated working electrode is used as a baseline for testing solid polymer surface coatings on working electrodes, and the difference in the observed current between the electrodes for a given potential is a quantitative indicator of the ability of the probe species to access the surface of the working electrode through the solid polymer electrolyte coating.

主权项

1. A method for quantitatively determining the presence of pinholes in an electrically insulating coating that has been electrochemically deposited on the surface of a conductive electrode material, comprising:
submersing the coated electrode material in a solution comprising a probe species dissolved in a solvent, wherein the probe species has a reversible electrochemical reduction and oxidation potential; applying a potential to the coated electrode material relative to a second electrode submersed in the solution; and measuring the current flowing between the coated electrode material and the second electrode.