To confirm the viability of a porous polyethylene (PE) separator for using in vanadium redox flow batted (VRFBs), we conduct a comparative electroanalytical and chemical stability studies of the PE separator ar Nafion 212 membrane. We characterize the physicochemical properties of the separator, such as water uptak dimensional change, and ion conductivity, and analyze its structural and compositional features using the mogravimetric analysis, scanning electron microscopy, and X-ray photoelectron spectroscopy. We also test ti chemical stability of the separator against highly oxidative V5+ ions and the cell performance of VRFB using separator to assess practical applicability. In chemical stability, the change of VO2+ ion to VO2+ ion is co] siderably lowered by the PE separator (0.01 mmol/L) than the Nafion 212 (0.27 mmol/L), which indicates th the PE separator possesses higher chemical stability. The energy efficiency of the VRFB with the PE separator lower than that obtained with Nafion 212. However, the chemical stability of PE separator is 27 times high, than that of Nafion 212, indicating that its use will promote the long-term operation of the VRFB system. Henc the PE separator can be considered a cost-effective option for VRFB operation, with appropriate modifications I its thickness, surface properties and pore structure.