Chain-extended poly(butylene adipate-co-terephthalate)-filled metallic oxides as new bio-based replacement for traditional environmentally harmful polymers in production of lithium-ion battery separators using printing method

This work introduces a novel high-performance lithium-ion battery (LIB) separator based on chain-extended poly(butylene adipate-co-terephthalate) (CE-PBAT) with great biodegradability, processability and flexibility. Four nano-minerals, i.e. , alumina, titania, silica and montmorillonite, were used to produce thin nano-porous LIB separators using a wet-manufacturing method by gravure printing. Chain-extension of PBAT by a reagent containing anhydrides turned the closed-holes of PBAT-based membrane with a porosity of 9.21% to a fantastic separator with well-dispersed nano-cavities (cavity size = 68.53 nm, the cavities' number density= 16.7μm −2 and porosity= 42.9%). Titania and alumina formed separators with the poorest microstructural features, porosity of 19.7 and 24.1%, respectively. Although silica had low impacts on the microstructural properties of CE-PBAT, nano-montmorillonite kept the porosity at 41.9% with the lowest undesirable effects on the microstructure. Montmorillonite greatly enhanced the wettability by 643%, while maintaining morphological properties. However, silica resulted in a 490% increase in the electrolyte absorption. The chain-extension reaction using nano-montmorillonite was found to be the best methodology for the production of CE-PBAT-based separators with the most efficient microstructural characteristics and wettability. The achieved ion conductivity of 2.08 mS.cm −1 for the CE-PBAT/montmorillonite-based LIB with the optimum formulation exhibited a 68–433% increase compared to the neat common commercial petroleum-based separators.