Poly(vinylidene fluoride)- and Poly(urethane acrylate)-Based Electrolytes for Solid State Batteries

Solid-state batteries (SSB) have better safety characteristics than conventional lithium-ion batteries which are based on flammable liquid electrolyte. A key enabler for SSB is the solid state electrolyte. Among possible candidates, polymer electrolytes have attracted a lot of attention as they offer a wide range of tunable structure, have good physical contact with electrodes and are easy to fabricate. This talk will include our recent work on two kinds of polymer electrolytes: Poly(vinylidene fluoride), or PVDF-based electrolyte and poly(urethane acrylate), or PUA-based electrolyte. PVDF polymer electrolyte is prepared by the solvent-casting method. We will discuss its performance in full cells using various kinds of cathodes. We will also discuss the effect of residual solvent on the eventual cell performance. PUA polymer electrolyte is prepared by a solvent-free method. Through controlling the degree of cross-linking, we were able to introduce PUA with gradient structure in the polymer electrolyte. This provides both good physical contact with electrode and good mechanical strength against lithium dendriate penetration. The LiNi_0.8Mn_0.1Co_0.1O₂|PUA|Li cell is evaluated and shows good performance.