Structure regulation of Zeolitic Imidazolate Framework-8 functionalized poly-m-phenyleneisophthalamide separator for enhancement on the comprehensive performance of lithium - ion batteries

Safety issues remain a major barrier to the large-scale application of high-energy-density storage systems. Uneven ion flow can lead to non-uniform lithium deposition and continuous dendrite growth. These problems greatly reduce the lifespan and safety of lithium-ion batteries (LIBs). In this work, a PMIA/ZIF-8 composite separator was fabricated by in-situ growth of zeolitic imidazolate framework-8 (ZIF-8) on the surface of a poly-m-phenyleneisophthalamide (PMIA) separator prepared via non-solvent induced phase separation (NIPS). The PMIA/ZIF-8 separator exhibits outstanding electrolyte affinity (411%) and high ionic conductivity (0.81 mS cm⁻¹), which are 3.2 times and 1.53 times that of the PP separator, respectively. In terms of battery performance, the battery employing the composite separator maintains a discharge capacity of 134.5 mAh g⁻¹ after 200 cycles, significantly outperforming the cell with a PP separator (108.4 mAh g⁻¹). Furthermore, the Li||Li symmetric battery equipped with the PMIA/ZIF-8 separator achieves stable cycling for over 600 h at 1 mA cm⁻², surpassing the performance of the PP separator (200 h). This work offers a feasible strategy for developing highly safe lithium-ion battery separators capable of efficiently inhibiting lithium dendrite growth.