Innovative bacterial cellulose and UiO-66 composites for superior zinc ion battery separator performance

Aqueous zinc-ion batteries (AZIBs) face challenges such as Zn dendrite formation and poor cycle stability. Here, we report an ambient-temperature in situ growth strategy to fabricate a bacterial cellulose-metal organic framework composite separator (BC@UiO-66) for AZIBs. In this approach, UiO-66 (a Zr-based MOF) grows uniformly on BC nanofibers, forming a 95 μm-thick film with hierarchical porosity and abundant Lewis acid sites. The resulting BC@UiO-66 separator facilitates Zn2+ diffusion through interconnected nanochannels and promotes uniform Zn deposition, thereby suppressing dendrite growth. A Zn||Zn symmetric cell using BC@UiO-66 operates stably for over 2400 h at 1 mA cm−2 and a Zn||MnO2 full cell retains 162.98 mAh g−1 after 1000 cycles at 1 A g−1 with ∼100% coulombic efficiency. These results demonstrate the efficacy of MOF-cellulose composite separators in extending AZIB cycle life.