Construction of Diversified Ion Channels in Lithium-Ion Battery Separator Using Polybenzimidazole and Ion-Modified Metal- Organic Framework

ABSTRACT: The preparation of separators using heat-resistant polymers is an effective approach to improve the safety of lithium-ion batteries (LIBs). However, separators using a single heat-resistant polymer compared with the composite modified polymer have low conductivities, which leads to low battery performances. In this study, for the first time, a heat-resistant separator was successfully prepared using an ion-modified metal-organic framework (MOF) and poly(aryl ether benzimidazole)(OPBI). Diversified ion channels were constructed by ion modification combined with phase inversion and physical mixing. The lithium-ion transmission efficiency and safety of the LIBs were effectively improved. The hybrid separator exhibited a satisfactory thermal stability (absence of shrinkage at 200 degrees C for 1 h), higher ionic conductivity (1.46 mS cm-1), and better electrolyte uptake rate. Moreover, the hybrid separator is conducive to inhibiting the growth of Li dendrites. A cell assembled with the hybrid separator delivered a reversible capacity of 157 mA h g-1 at 0.5 C. The capacity retention of the cell was up to 94% after 200 cycles. Thus, the hybrid membrane is a valuable candidate to enhance the safety and electrochemical properties of LIBs.