Polymer Nanoparticles as Functional Fillers for Composite Electrolytes for Batteries

Different nanofillers, such as inorganic nanoparticles or nanofibers, are commonly used to design composite electrolytes with superior mechanical and electrochemical properties for batteries. As an alternative, we review here the recent use of polymeric nanoparticles obtained by drying nanolatexes synthesized by emulsion polymerization. These polymeric nanoparticles offer key advantages vs inorganic nanoparticles, such as scalable synthesis, controllable chemical nature, size control, easy surface functionalization, low density, and excellent dispersion within polymeric matrices. First, we will discuss the synthetic method of sulfonamide-functional poly-(methyl methacrylate) nanoparticles (LiNPs) in order to control the particle chemical nature, surface functionality, and size between 20 and 100 nm. Next, we will show how these polymeric nanoparticles can be used to prepare composite electrolytes with improved mechanical properties, high ionic conductivity, and/or lithium single-ion conduction. Finally, the excellent performance of the different composite electrolytes in both lithium- and sodium-metal batteries will be shown.