Enhanced electrochemical performance of P(VDF-HFP)-PVAc-based composite solid polymer electrolytes with spherical shape ZrO2 nanoceramic for lithium-ion battery applications

Solid polymer electrolytes (SPEs) are a promising substitute, offering splendid benefits such as improved energy density and safety compared to liquid electrolytes. However, low ionic conductivity, poor mechanical strength, weak interfacial contact, and electrode metal corrosion may still be critical problems in SPEs. Here, a composite solid polymer electrolyte (CSPE) is prepared using the standard solution casting technique, incorporating P(VDF-HFP)-PVAc-LiTFSI-EC [poly(vinylidene fluoride-hexafluoro propylene)-poly(vinyl acetate)-lithium bis-trifluoromethanesulfonylimide-Ethylene carbonate] with hydrothermally derived spherical shape ZrO2 nanocrystals (NCs) as a passive ceramic filler. Notably, incorporating 5wt% ZrO2 NC in the CSPE leads to a notable threefold time increase in ionic conductivity compared to the SPE without ZrO2 NC. This improvement is mainly attributed to spherical shape ZrO2 NC facilitating Li+ migration channels and immobilizing free anions, likely by suppressing the crystallinity of the CSPE and its Lewis acid-base nature. Additionally, CSPE demonstrates high mechanical strength; excellent thermal stability; a wide electrochemical window; and favorable electrolyte affinity. This promising material is well-suited for developing robust and efficient electrolytes for various applications.