Polybenzimidazole Composite Separators Engineered from MOFs-HNTs Composites Applicated in Lithium-Ion Batteries

Abstract

Incorporating inorganic nanostructured materials into polymeric separators for lithium-ion batteries (LIBs) enhances properties such as ionic conductivity, electrolyte wettability, and thermal resistance. However, poor interfacial compatibility between inorganic materials and the polymeric matrix remains a significant challenge. In this study, Zr-based UiO-66 metal-organic frameworks (MOFs) is employed as an interfacial binder between halloysite nanotubes (HNTs) and a poly-(arylene ether benzimidazole) (OPBI) matrix, preparing porous separators using the non-solvent phase separation (NIPS) method. The UiO-66 MOFs promote strong adhesion of HNTs to the OPBI chains, creating a more cohesive inorganic-organic system, as confirmed by molecular dynamics (MD) simulations of binding energy. The resulting OPBI@M-H10 composite separator exhibits high porosity (80%), an electrolyte absorption capacity of 377%, and an ionic conductivity of 1.59 mS·cm⁻¹. Furthermore, LiFePO₄ half-cells assembled with this composite separator show a discharge capacity of 161 mAh·g⁻¹ and a retention rate of 97.96% after 200 charge-discharge cycles. The separator also demonstrates excellent electrode stability in the plating/stripping test of Li symmetric cells, lasting up to 1600 hours and effectively inhibiting dendrite growth on the Li anode. This approach provides a promising solution for high-performance LIBs separators and paves the way for advancements in LIBs technology and energy storage applications.