The ZnHCNF fiber with ultrahigh-content gradient-distributed single-atom Zn-N₄ catalytic sites driving selective deposition and encapsulation of Li ions for Li metal anode

The troubling dendrite growth is still a challenging for Li metal battery commercial popularity. Herein, a single-atom catalyst ZnHCNF possessing of ultrahigh-content (20.3 wt%) of Zn implanted in 1D free-standing cross-linked hierarchically porous carbonaceous nanovesicles fiber is prepared and used as electrocatalytic collector for the Li metal anode. Interestingly, the vesicle walls of ZnHCNF present an obvious Zn concentration gradient from inside to outside and the nucleation deposition of Li ions catalyzed by the Zn-N₄ active sites occurs preferentially at the inner walls of the vesicle. This inside-out deposition and encapsulation orientation eliminates the formation of Li metal dendrites. A symmetric cell consisting of a ZnHCNFLi composite anode has a very long cycle life of 3000 h. High property was obtained when matched with typical commercial lithium iron phosphate cathode for the ZnHCNFLi//LFP full cell. This unusual electrocatalytic collector has great practical application potential in realizing dendrite-free Li metal anode.