Manipulating Horizontal Zn Deposition with Indium Salt Additive for Anode-Free Zn Batteries

Anode-free zinc batteries offer reduced weight and simplified production compared to traditional zinc metal batteries, but challenges such as dendrite formation and parasitic reactions limit their efficiency and cycle life. In this study, we present an effective strategy to form a zincophilic interphase in situ via indium co-deposition during cycling, using InCl3 as an electrolyte additive. Zinc plating/stripping processes were investigated using operando electrochemical quartz crystal microbalance with dissipation monitoring (EQCM-D) and hydrodynamic spectroscopy, combined with other ex situ techniques. Our findings demonstrate that the indium-containing electrolyte additive has three functions: it induces oriented zinc deposition through prenucleation, suppresses the hydrogen evolution reaction by forming an indium intermediate layer, and suppresses zinc hydroxide sulfate (ZHS) formation by consuming OH– with In2O3/InOOH formation. These advantages result in a decreased overpotential and higher Coulombic efficiency, enhancing the design of highly reversible anode-free zinc batteries.