Active or passive? The role of ceramic particles in polymer composite electrolytes

There exist two main electrolyte categories for solid-state batteries, based either on ion-conductive ceramic or polymeric materials.

Due to their respective short-comings, composites between these materials are often being promoted to create functional systems, and often can improved properties be seen in systems which comprise polymer electrolytes with active ceramic fillers.

However, the mechanism of ionic conduction is elusive, and it remains unclear how the fillers contribute to increased conductivity; i.e., if they contribute by their bulk conductivity.

Traditionally, passive (non-conductive) fillers have also been incorporated in polymer electrolytes, and similar positive effects have been observed. It is often speculated that new ionic transport pathways are created at the interface between the two materials.

Recently, my team has explored passive Li-containing fillers in Li-conductive polymer electrolytes, where upon exceptionally high Li-ion conductivity has been observed.

The ambition of this project is to explore this further by a larger materials platform, systematic comparison between different types of fillers – active and passive – in the electrolytes, and by a range of advanced characterization methods and computational techniques, whose combination is new for this category of materials.

Thereby, not only will improved electrolyte systems be constructed, but main insights achieved on what controls ionic transport in these complex systems.