In situ nanoscale insights into the interfacial degradation of Zn metal anodes

Abstract

Zn metal batteries are highly attractive because of their high theoretical specific capacity, intrinsic safety and resource availability. However, further development is significantly hindered by low Coulomb efficiency, which is closely linked to reaction processes occurring at electrode/electrolyte interfaces. Herein, we have achieved a real-time visualization and comprehensive analysis of the interfacial evolution of Zn metal anode via in situ AFM in organic and aqueous electrolytes, respectively. The processes of uneven nucleation, dendrite growth, the ZnO formation and the dissolution of Zn substrate are directly probed in aqueous electrolyte, which induces interfacial deterioration and ultimately results in battery failure. In organic electrolyte, the in situ observations show that the homogeneous nuclei form on the Zn surface to induce the dendrite-free deposition, however, exhibiting poor Zn plating/stripping reversibility. This work delves into the dynamic evolution and electrochemical behaviors regulated by solvents, which provides in-depth understanding of structure-reactivity correlations and further interfacial engineering.