An in-situ grown high-efficiency Zn-terephthalate metal–organic framework/ZnO hybrid interface protection layer to achieve highly reversible dendrite-free Zn anodes

Lately, aqueous zinc-ion batteries (AZIBs) have stood out from numerous power storage equipment owing to their considerable theoretical capacity, convenient operation and trustworthy safety; unfortunately, inevitable dendrite growth and severe side reactions on the surface of Zn metals degrade the reversibility of Zn anodes. Herein, a high-efficiency Zn-terephthalate metal–organic framework (Zn-TPA-MOF)/ZnO hybrid interface protection layer (Zn-TPA-MOF/ZnO) grown in-situ on the pre-oxidized Zn foil surface is proposed to suppress the side reactions and dendrite growth for improving the reversibility of Zn anodes. The Zn-TPA-MOF/ZnO hybrid interface protection layer with strong hydrophobicity/zincophilicity facilities the rapid desolvation of Zn(H2O)62+, improves Zn2+ deposition kinetics, homogenizes the surface electric field and simultaneously constrains the 2D diffusion of Zn2+. Moreover, the Zn anode with the hybrid protection film exhibits high ionic conductivity (3.86 mS cm−1), low electrical conductivity (0.00607 mS cm−1), large transfer number of Zn2+ of 0.70 and low activation energy (55.87 kJ mol−1), efficiently accelerating the interface transfer of zinc ions during electrochemical reactions. Therefore, the Zn-TPA-MOF/ZnO@Zn||Zn-TPA-MOF/ZnO@Zn cell possesses an extremely long cycling life of over 3020 h at 1 mA cm−2/1 mAh cm−2, 40 times longer than the cell of Zn||Zn (76 h); moreover, the Zn-TPA-MOF/ZnO@Zn//Cu asymmetric cell demonstrates a superior cycling life of over 4200 cycles at 0.5 mA cm−2/0.25 mAh cm−2, and the average Coulombic efficiency of the cell is as high as 99.65%. Besides, the Zn-TPA-MOF/ZnO@Zn//VS4 full cell displays a reversible capacity of 106.6 mAh/g with the high capacity-retention of 121.39 % at 5 A/g after 1000 cycles. This investigation proposes a feasible strategy to in situ grow hydrophobic/zincophilic hybrid interface protection layer to achieve highly reversible Zn anodes.