Study on the effect of different shapes of HKUST-1 based cellulose battery separators on the performance of zinc batteries

This study examines how the morphology of HKUST-1-based cellulose separators affects the performance of aqueous zinc-ion batteries. Zinc-ion batteries are attractive for large-scale energy storage due to their safety, low cost, and environmental benefits, but challenges like zinc dendrite formation and cathode instability remain. Three HKUST-1 morphologies (orthorhombic octahedral, semi-fused, and fully-fused) were synthesized and integrated with cellulose nanofibers to create composite separators. The fully-fused HKUST-1 (F-HK) separator demonstrated superior performance due to its amorphous network structure, which enhanced mechanical strength, promoted uniform zinc-ion deposition, and suppressed dendrite growth. In Zn//Cu half-cells, the F-HK separator exhibited a low nucleation overpotential of 47 mV and an average Coulombic efficiency of 99.98 % over nearly 500 cycles. In Zn//MnO 2 full cells, it retained over 80 % capacity after 400 cycles at 1 A·g −1 with near-100 % Coulombic efficiency. Additionally, the F-HK separator showed significantly enhanced mechanical strength compared to pristine cellulose separators. The findings underscore the pivotal role of morphology in enhancing separator performance and offer meaningful insights for creating high - performance MOF - based separators for aqueous zinc - ion batteries. • Fully-fused HKUST-1 separators enhance zinc-ion battery performance significantly. • Amorphous structures suppress zinc dendrite growth and improve stability. • Innovative direct co-grafting method optimizes ionic conductivity in separators. • Retained >80 % capacity after 400 cycles with nearly 100 % Coulombic efficiency. • Study provides insights into morphology effects on aqueous zinc-ion batteries.