2D Dynamic Heterogeneous Interface Coupling Endowing Extra Zn2+ Storage

Abstract

AbstractAqueous 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.