Aqueous rechargeable batteries are appealing alternatives for large-scale energy storage. Reversible cycling of high-energy aqueous batteries has been showcased using highly concentrated aqueous electrolytes, which leads to a significantly suppressed water activity and formation of a stable solid–electrolyte interphase (SEI). However, the high salt concentration inevitably raises the cost and compromises the environmental sustainability. In this presentation, the feasibility of cycling aqueous cells in dilute electrolytes will be discussed with examples. Advanced operando characterizations are utilized to unveil the complex interfacial chemistry in dilute electrolytes, taking into account material reactivity and interfacial compatibility. A high-throughput electrolyte screening platform, which is able to automatize coin cell assembly and testing processes, will be coupled with machine learning to accelerate material discovery of sustainable aqueous batteries.