Not all fugitives are bad: The case for using them to form low tortuosity - high porosity electrodes

Abstract

This work focuses on the inclusion of an insoluble fugitive phase during slurry processing to form composite battery electrodes. The fugitive phases consist of natural derived products like alginic acid, sucrose, rice and potato starch, and carrageenans such as Irish Moss and synthetic pore-formers based on polymethyl methacrylate. The fugitive phases can be anaerobically thermally removed (350 °C) during binder crosslinking and electrode drying steps, resulting in electrodes with low tortuosities (approaching theoretical Bruggemann limits for spherical particles) and high porosities approaching 80%. The resulting ∼3 mg/cm² loaded electrodes suffer from poor electrical connectivity, lowering the effective material utilization, but represent an approach that could be utilized for the formation of solid-state batteries with infilling of materials into well-defined pores and optimized transport pathways.