Comparative Study on the Transport Characteristics of Lithium Battery Electrolyte Molecules in the Vulcanized EPDM and HNBR Matrices

The equilibrium swelling method was employed to examine the transport characteristics of electrolyte components in hydrogenated nitrile butadiene rubber (HNBR) and ethylene propylene diene monomer (EPDM). The transport curves, diffusion coefficients ( D ), sorption coefficients ( S ), and permeation coefficients ( P ) of electrolyte components within the rubber matrix were computed, and the effect of filler quantity on the values of D , S , and P was examined. The results indicate that the transport curves and transport coefficients of EPDM are lower than those of HNBR; the phenomenon of which can be attributed to the similarity in polarity between the electrolyte components and HNBR. The increase in kaolin content reduced the electrolyte component resistance of EPDM and HNBR. The compatibility of rubber and electrolyte components was evaluated, and a mathematical model was established using the Flory–Huggins interaction parameter ( χ 3D ) and R a value. The results show that the prediction model has an inverse proportion function relationship. This work provides a reference for the selection of sealing materials for lithium batteries.