Tailored graft polymerization on SiO2 nanoparticle by sulfonate styrene and methyl methacrylate and evaluation of their electrochemical performance in gel polymer electrolyte based on poly (vinylidene fluoride) for Li-ion batteries application

Abstract

An organic–inorganic hybrid nanoparticle was synthesized based on poly (methyl methacrylate-co-sulfonate styrene) (P(MMA-co-SSt)) grafted on silica (SiO₂) nanoparticles via free radical polymerization. The SiO₂-g-P(MMA-co-SSt) was blended with poly (vinylidene fluoride) (PVDF) for the preparation of porous gel polymer electrolyte (GPE) membranes through the phase inversion technique for lithium ion batteries (LIBs) application. This work investigated the crystallinity, porosity, chemical structure, electrolyte absorption, and electrochemical and mechanical characteristics of the membranes. The results showed that the hybrid nanoparticle, containing sulfonated and ester groups along with SiO₂ nanoparticles carrying OH groups, facilitated positive connections with Li⁺ ions, enhanced amorphous regions, boosted porosity, and significantly absorbed electrolytes. This consequently enhanced the electrochemical performance of PVDF blends. The PVDF/SiO₂-g-P(MMA-co-SSt) GPE displays notable characteristics, including a substantial electrochemical window up to 4.7 V and ionic conductivity of 2.28 mS cm⁻¹ at room temperature. Furthermore, the NMC/Li cell based on synthesized GPE exhibits a capacity retention of 82.73 % (120.6 mAh/g) with a columbic efficiency of 92.26 % after the 50th cycle. Besides, the membrane’s mechanical properties were suitable (the modulus of 13.51 MPa at room temperature). These findings suggest that the synthesized GPE can hold promise for developing safe and high-performance LIBs.