Using Scanning Ion Conductance Microscopy to Measure Ion Conductivity and Permeability in Porous Materials

Composite electrodes can significantly improve the performance of an electrochemical device by maximizing surface area and active material loading. Typically, additives such as carbon are used to improve conductivity and a polymer is used as a binder leading to a heterogeneous surface film with thickness on the order of tens of microns. For such composite electrodes, good ionic conduction within the film is critical to capitalize on the increased loading of active material and surface area. Ionic conductivity within a film can be tricky to measure directly and homogenization models based on porosity are often used as a proxy. Scanning Ion Conductance Microscopy (SICM) has traditionally been a topography-mapping microscopy method. We will outline a new function and demonstrate SICM’s capacity for measuring ion conductivity within lithium-ion battery composite electrodes.