An ionic liquid-integrated poly(vinylidene fluoride-co-hexafluoropropylene)/Li₇La₃Zr₂O₁₂ composite membrane for...

Lithium-ion batteries (LIBs) with organic liquid electrolytes face safety and stability challenges. Solid-state electrolytes are promising but hindered by low ionic conductivity and poor interfacial contact. This study demonstrates an integrated additive strategy to enhance the performance of composite polymer electrolytes (CPEs). By incorporating a dispersant poly(4-styrenesulfonic acid) lithium salt (PSSLi), a plasticizer (succinonitrile, SN), and an ionic liquid (N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide, Pyr₁₄TFSI) into a (poly(vinylidene fluoride-co-hexafluoropropylene), PVDF-HFP)/Li₇La₃Zr₂O₁₂ (LLZO) polymer matrix, a multicomponent hybrid electrolyte system was developed. The addition of SN and Pyr₁₄TFSI effectively disrupts the polymer crystallinity and reduces interfacial impedance, facilitating efficient lithium-ion transport. As a result, the optimized CPE achieves an ionic conductivity of 4.40 × 10^-4 S cm^-1 at room temperature. The LiFePO₄ (LFP)//Li cell delivers an initial specific capacity of 157 mAh g^-1, demonstrating an excellent capacity retention of 95% after 100 cycles at 0.1C and room temperature. Moreover, the assembled commercial LiNi_0.8Co_0.1Mn_0.1O₂ (NCM-811)//SiO@C full cell exhibits an impressive specific capacity of 188 mAh g^-1, retaining 74.4% of its capacity under identical conditions. These findings underscore the potential of this multicomponent system for high-performance quasi-solid-state battery applications.