Side-Reactions of Polyvinylidene Fluoride and Polyvinylidene Chloride Binders with Aluminum Chloride-Based Ionic Liquid Electrolyte in Rechargeable Aluminum-Batteries

Electrode fabrication often relies on procedures from Lithium-Ion Batteries (LIBs), including the use of Polyvinylidene fluoride (PVdF) as a binder. However, PVdF reacts with Al2Cl7- in the RAB electrolyte, making it unsuitable for new battery types.

The literature lacks details on the products formed, changes in the ionic liquid electrolyte, and the implications for electrochemical performance. With potential European Chemical Agency (ECHA) restrictions on per- and polyfluoroalkyl substances (PFAS) by 2025, Polyvinylidene chloride (PVdC) is being explored as an alternative binder. In contact with AlCl3:EMImCl (1.50:1.00) electrolyte, both, PVdF and PVdC transform into amorphous carbon during dehydrofluorination (DHF) and dehydrochlorination (DHC), respectively, as confirmed by Raman spectroscopy.