Flexible PVDF‐HFP, Nickel MOF‐based Hybrid Membrane as an Efficient Electrolyte for Lithium‐Ion Batteries

Abstract The present investigation demonstrates a highly stable composite polymer electrolyte (CPE) membrane (NiPF6), designed to enhance the performance of solid‐state lithium‐ion batteries. The new CPE membrane has been fabricated by the blending of Ni‐BDC metal‐organic framework (MOF) (BDC: 1,4‐benzenedicarboxylate), lithium salt, and PVDF‐HFP (poly (vinylidene fluoride‐co‐hexa fluoropropylene)). The XRD of the CPE membrane clearly shows the presence of 2D Ni‐BDC MOF. The mechanical properties and flame test validate the robustness of the membrane. The detailed morphological study of the membrane shows the presence of a porous surface and a layered structure. The CPE membrane exhibits a high ionic conductivity i. e. 1.5×10 −4 S/cm at room temperature, which has increased to 5.99×10 −4 S/cm at 55 °C. Considering the high ionic conductivity of the CPE membrane it has been used as an electrolyte for Li‐ion cells. The Li‐ion cell fabricated using the Ni‐BDC CPE membrane has achieved a discharge capacity of 169.52 mAh/g @ 0.1 C rate, with impressive capacity retention(97 %). The cell showed a 149 mAh/g discharge capacity @1 C with 85 % retention over 300 cycles. Further, it delivered a capacity of around 128.55 mAh/g @ 2 C with 81 % capacity retention at 200 cycles. This enhancement is attributed to the incorporation of 2D Ni‐BDC MOF, which has a porous and layered structure that might significantly improve the Li‐ion conduction path. Hence, the enhancement in ionic conductivity is self‐explanatory. The stable Li‐ion conduction path might be formed at a higher C rate, hence the retention capacity has been increased @2 C rate compared to 1 C. More significantly, this is a promising approach for advancing solid‐state lithium‐ion battery technology by using new composite polymer electrolytes with efficient performance at room temperature.