In-situ polymerized high-ionic conductivity vinyl-based copolymer in electrospinning membrane for lithium-ion batteries

The inferior ionic conductivity and high electrode/electrolyte interfacial impedance of solid polymer electrolytes (SPEs) restrict their broader application in solid-state lithium-ion batteries (SSLIBs). Herein, vinyl-based cross-linked solid polymer electrolytes (SPE-PIV) were prepared by in-situ polymerization. Vinylene carbonate (VC) and ionic liquid (1-vinyl-3-isobutyrate ethyl imidazole bis (trifluoromethyl sulfonyl) imide (VBIM-TFSI)) were used as monomers, and octamethyacryl-POSS (octaMA-POSS) was used as the cross-linker with the support of POSS-enhanced PVDF membrane (POSS/PVDF) to prepare SPE-PIV. The POSS brings more stability and more free volume to SPEs. Poly(ionic liquid) possesses greater dielectric constant and higher thermal and chemical stability. So it is found that SPE-PIV, a cross-linked polymer, exhibits superior electrochemical properties with the ionic conductivity of up to 9.02 × 10⁻⁴ S cm⁻¹ at 30 °C and an electrochemical stability window of 5.4 V, and a high lithium-ion transference number of 0.64. With the combined benefits of the in-situ polymerization and electrospinning membrane, the interfacial performance was enhanced. This work offers a general strategy for superior electrochemical properties and interfacial performance of SPEs with further insights into high-performance SSLMBs.