Manipulating\nHorizontal Zn Deposition with Indium\nSalt Additive for Anode-Free Zn Batteries

Anode-free zinc batteries\noffer reduced weight and simplified\nproduction\ncompared to traditional zinc metal batteries, but challenges such\nas dendrite formation and parasitic reactions limit their efficiency\nand cycle life. In this study, we present an effective strategy to\nform a zincophilic interphase <i>in situ</i> via indium\nco-deposition during cycling, using InCl<sub>3</sub> as an electrolyte\nadditive. Zinc plating/stripping processes were investigated using <i>operando</i> electrochemical quartz crystal microbalance with\ndissipation monitoring (EQCM-D) and hydrodynamic spectroscopy, combined\nwith other <i>ex situ</i> techniques. Our findings demonstrate\nthat the indium-containing electrolyte additive has three functions:\nit induces oriented zinc deposition through prenucleation, suppresses\nthe hydrogen evolution reaction by forming an indium intermediate\nlayer, and suppresses zinc hydroxide sulfate (ZHS) formation by consuming\nOH<sup>–</sup> with In<sub>2</sub>O<sub>3</sub>/InOOH formation.\nThese advantages result in a decreased overpotential and higher Coulombic\nefficiency, enhancing the design of highly reversible anode-free zinc\nbatteries.