An in-depth study of heterometallic interface chemistry: Bi-component layer enables highly reversible and stable Zn metal anodes

Aqueous zinc (Zn) metal batteries (ZMBs) have attracted much attention because of their high safety and energy density compared with currently used non-aqueous lithium-ion batteries. However, challenges remain toward their practical applications, originated from the Zn dendrite growth and hydrogen evolution on Zn anodes. To address these issues, we develop an advanced Zn anode (ZnIn3@In-Zn) by constructing a bi-component layer, which consists of indium (In) particles surrounded with ZnIn3 alloy. Such an artificial layer induces highly reversible Zn depositing/stripping, thus keeping the anode dendrite free. Additionally, this layer yields high hydrogen evolution overpotential, ensuring the anode with high charge/discharge Coulombic efficiency. As a result, a ZnIn3@In-Zn//ZnIn3@In-Zn symmetric cell presents a low depositing/stripping overpotential of 15 mV with ultra-long cyclic lifespan over 10,000 h under a current density of 1 mA cm-2. Moreover, the ZnIn3@In-Zn//Na3V2(PO4)3 full cell displays an excellent cyclic stability with a high Coulombic efficiency of 99.8%. The contribution of the as-constructed bi-component layer has been understood by in-situ spectral characterization combining with theoretical calculation. Our fundamental findings offer a deeper insight into the heterometallic interface chemistry of Zn anodes, which helps realize long-life cycle ZMBs.