Optimizing HDPE separator properties through thermoplastic elastomer loading and manufacturing process for improved lithium-ion battery electrochemical performance

The impact of thermoplastic elastomer loading and the manufacturing parameters on the (high-density-polyethylene)-based separator performance in the lithium-ion battery was investigated. It was indicated that the spherical-shaped cavities with 5.85 ± 2.2 μm diameter were formed by lower thermoplastic elastomer amounts as well as the tension levels (during the manufacturing process), whereas the oval-shaped cavities with a decrease in size by 1.65 ± 0.68 μm were created with an increase of tension tic elastomer contents. An ~ 8% increase in the separator porosity by raising the thermoplastic elastomer and tension amounts (simultaneously) was detected. Additionally, the separator wettability was enhanced by ~ 34% by increasing the thermoplastic elastomer content, and a 150% improvement was obtained by tension increment. A significant reduction was found in the high-density-polyethylene resistance, solid electrolyte interface thickness, and electrolyte resistance from 860 to 330 Ω, 80 to 50 nm, and 13 to 4 Ω with the thermoplastic elastomer and tension level, respectively. An enhancement in the ion conductivity from 0.78 to 1.59 × 10⁻³ S cm⁻¹, along with an increase in the LIB's capacity from 35.92 to 52.41 × 10⁴ A s kg⁻¹ and 35.20 to 51.87 × 10⁴ A s kg⁻¹ during the charge and discharge processes, respectively, was caused by the aforementioned phenomenon.