Boosting tough metal Zn anode by MOF layer for high-performance zinc-ion batteries

Metal-organic frameworks (MOFs) have been used to stabilize the metal zinc anode, yet the developed coating materials ignore the influence of intergranular space on deteriorating Zn electrode. Herein, we propose the channel sizes of MOFs as the key control factor to balance the zinc ion flux and Zn2+ desolvation behavior within the channels and between the intergranular spaces. Among three coating layers made by MOFs, the MOF-5W layer with confined spaces and channels is capable to promote the spontaneous desolvation process. The activated surface sites on MOF-5W endow the intergranular channels with accelerated ion transportation and spontaneous Zn2+ desolvation. Two kinds of migration paths are well-matched, as the MOF-5W@Zn anode shows Zn stripping/plating over 5000 cycles at 40 mA cm‒2, as well as cycling stability of 1050 h with high areal capacity of 10 mAh cm‒2. The findings enlighten the innovative research for tough Zn anode.