Cerium Oxide Functionalized Nanoparticles as HF Scavenger in PVdF-HFP quasi-solid-state Electrolytes

The increasing reliance on renewable energy sources has raised the demand for more efficient energy storage solutions. Quasi-solid-state electrolytes (QSSEs) enable the replacement of graphite anodes with metallic lithium ones, offering improvements in both capacity and performance. One method to create a QSSE involves using a polymer matrix that retains a minimal amount of solvent and incorporating a lithium salt to support Li-ion mobility. Salts with fluorinated anions are commonly employed, but these tend to hydrolyse in moist environments, producing HF, which degrades the cathode. This study focused on exploring the use of functionalized cerium oxide nanoparticles as HF scavengers within the electrolyte, aiming to reduce cathode degradation. After functionalizing the nanoparticles with a specific silane, membranes composed of PVdF-HFP and varying amounts of CeO₂ were fabricated via solvent casting, and their physical and electrochemical characteristics were analysed. Once the optimal composition was identified, the scavenging performance was tested by introducing water and monitoring any alterations in the material’s behaviour. The cell using the nanofiller-enhanced membrane maintained a longer lifespan, even under moisture exposure, compared to the one with the plain polymer. In summary, incorporating nanofillers into QSSEs may offer not only the known performance benefits but also improved resistance to moisture by scavenging residual water in the system.