Steering and in situ monitoring of drying phenomena during film fabrication

Abstract

During film fabrication, the phenomena of crack formation and delamination are often observed, dramatically hindering the discovery and characterization of new materials for energy applications. In this work, we report on a novel approach to fully steer the drying parameters or “knobs” that are commonly used during electrode manufacture. It allows us to precisely in situ control and monitor the solvent-specific evaporation rates that affect the development of suspension composition during drying. We managed to control the capillary stress inside the layer by precisely controlling the selectivity of solvent evaporation. Large cracks result when the surface tension increases over time and layer delamination occurs. When using an n-propanol/water system, critical crack formation is achieved when water is enriched by decreasing the gas exchange during drying or preloading the gas phase with water vapor. High gas exchange rates inhibit the water’s enrichment, and therefore, only small surface cracks develop. The experiments also surprisingly indicate that the drying temperature has no significant effect on crack formation. These results are of fundamental meaning for the future development of electrodes as the drying step has a high impact on the products specification and now can be ultimately controlled. The future development of electrodes will surely benefit from this achievement in the controlled fabrication of films for a variety of applications.