Tổng hợp và đánh giá tính chất điện hóa của màng điện giải gel polymer PEO/PVDF/SiO2/LiTFSI sử dụng cho pin Li-ion

Solid polymer electrolytes (SPEs) have gained significant attention to replace liquid electrolyte in the conventional Li-metal batteries (LMBs) for the safety issues. However, SPEs with poly(ethylene oxide) (PEO) as the main polymer often encounter low ionic conductivity at room temperature and weak mechanical properties, which obviously hinder the practical application of SPEs batteries. Therefore, to address these challenges, a proposed strategy is employing the composite polymer electrolyte based on blended PEO and polyninylidene fluoride (PVDF) polymer matrix combined with inorganic filler like silica (SiO2) nanoparticles and lithium bis(trifluoromethane sulfonyl)imide (LiTFSI) salt served as plasticizer and ionic conducting agent. PVdF polymer with high melting temperature and good mechanical strength helps improve the thermal stability and relative mechanical properties of the SPE membrane. The inclusion of nano-sized SiO2 necessarily facilitate the homogenous diffusion flux of lithium-ion and inhibiting lithium dendrites. This study investigates the influence of PVDF concentration on the composite polymer at a fixed 5% wt. of SiO2 and 15% wt. LiTFSI. The thickness of SPEs films is controlled in range of 50 – 120 µm. The surface and cross-sectional morphology of the GPE membranes revealed that the addition of PVdF enhanced the connection and reduced the occurrence of defects on the membrane surface. In comparing to PEO based SPEs. The composite polymer electrolyte achieved an impressive ionic conductivity of 2,32×10^-4 S/cm (at 60 oC) and higher on-set oxidation voltage ~ 3,9 V vs Li+/Li.