2D Dynamic Heterogeneous Interface Coupling Endowing Extra Zn²⁺ Storage

Abstract Aqueous zinc‐ion battery (AZIBs) is expected to be an ideal device for large‐scale energy storage for its high safety and low cost. However, it is still a challenge to achieve both high energy density and high stability. Herein, in situ liquid‐phase growth exfoliation is developed to obtain V₅O₁₂ nanosheets, which is then combined with Ti₃C₂ nanosheets to construct two‐dimensional heterostructure (2D HVO@Ti₃C₂) with interfacial VOTi bonds. 2D HVO@Ti₃C₂ exhibits a dynamic interface coupling during discharging/charging, accompanied by break/reconstruction of interfacial VOTi bonds. The dynamic interface coupling provides a reversible electron transfer channel and endows the inert Ti₃C₂ with electrochemical activity in AZIBs, making it an additional electron acceptor and donor, and promoting the insertion of more Zn²⁺. Therefore, a capacity beyond the theoretical capacity of HVO is obtained for the HVO@Ti₃C₂. Additionally, the reversible 2D dynamic interface coupling can also effectively alleviate the structural damage during the cycling process. Then, the ultra‐high capacity (457.1 mAh g^‐1 at 0.2 A g^‐1, over 600 mAh g^‐1 based on the mass of HVO) and high stability (88.9% capacity retention after 1000 cycles at 5 A g^‐1) are achieved. This interface coupling mechanism provides an exciting strategy for the high energy density and high stability of AZIBs.