In-situ MOFs coating on 3D-channeled separator with superior electrolyte uptake capacity for ultrahigh cycle stability and dendrite-inhibited lithium-ion batteries

Lithium-ion batteries have been regarded as the most potential energy storage system due to their high energy density and theoretical capacity. However, conventional separators suffer from low electrolyte absorption, poor thermal and cycling stability, short circuits caused by dendrite growth. Herein, an effective approach was proposed to explore MOFs-based 3D-channeled separator via in-situ growth of ZIF-8 coating, which could significantly improve cycle stability and inhibit dendrite growth. Specifically, PLA membrane with 3D-channels was prepared by directional electrospinning and dopamine-induced assembling of MOFs in-situ growth onto the specified surface. By manipulating solvents, the desirable robustness of MOFs coatings could be accomplished through morphological assembly. Based on MOFs-architectured coating and microporosity, the excellent thermal stability (no change in size at 120 °C) and superior electrolyte uptake ability (290%) were finally obtained for the biobased separator. The assembled Li-ion battery exhibited ultrahigh cycle stability (capacity retention rate, 98.78% after 200 cycles at 1C rate) and preferable resistance to dendritic penetration, higher than those of the publicly reported. The excellent performance was attributed to the multiple 3D-channeled pathways for Li+ provided by MOFs and coating morphology. This study shows the potential for the development of next generation energy storage devices with excellent cycle stability.