Reducing the ecological and economic footprint of electrochemical energy storage requires battery and storage concepts beyond standard intercalation-type Li-ion batteries. Current technologies suffer from the need of expensive, toxic, and flammable materials that are often obtained under harsh environmental and socioeconomic conditions . Amongst the possible alternatives, iodine-based aqueous systems, such as iodide hybrid supercapacitors , zinc iodine batteries , or zinc iodide flow batteries are highly promising considering their performance, sustainability, and environmental aspects. However, to see their more widespread use in mobile or stationary applications, energy density, rate capability, and long-term stability need to become competitive with current Li-ion battery technology.