Membrane with horizontally rigid zeolite nanosheet arrays against zinc dendrites in zinc-based flow battery

Zinc-based flow batteries are recognized as one of the most promising stationary energy storage systems due to their advantages of high energy density and low cost. However, the zinc dendrites are great challenge for safe operation of battery, which can pierce membranes and further lead to short circuit. In this work, rigid zeolite nanosheet (ZN) arrays were horizontally dispersed in polymer membrane matrix, which formed a strong barrier against zinc dendrites. On the one hand, these suspended ZNs with well-defined internal channels effectively reinforced the ion recognition ability of membrane, and the membranes embedded ZNs exhibited superior battery performance with coulombic efficiency of ∼98.5% and energy efficiency of ∼83.6% at 80 mA cm⁻². On the other hand, the rigid ZN arrays endowed membranes better mechanical strength and stronger puncture resistance, which significantly extended the cycle life of battery and prevented the membrane from being pierced by zinc dendrites. The cell equipped with membrane embedded ZNs ran stably more than 550 cycles without significant performance degradation, which is much more than the commercial Nafion 212 membrane (∼120 cycles). This study provides an effective approach to defend against zinc dendrites and construct safe and efficient zinc-based energy storage devices.