Green Electrolytes for Aqueous Ion Batteries: Towards High-Energy and Low-Temperature Applications

Aqueous battery systems are increasingly recognized for their potential as environmentally friendly next-generation energy storage solutions. However, their commercialization faces challenges due to the need for electrolytes that can operate stably at high voltages and in low-temperatures. Traditional approaches to address these issues often involve materials that compromise the green nature. This review highlights the importance of developing environmentally friendly materials to improve the performance of aqueous electrolytes under high voltage in different types of aqueous electrolytes such as water-in-salt, molecular crowding electrolytes, eutectic electrolytes and cosolvents. In addition, we review advances in different types of aqueous electrolytes focused on using sustainable materials to achieve stable electrolytes at low-temperature by suppressing water crystallization and lowering the freezing point. By integrating these innovations, we envision a future where aqueous batteries offer both high performance and eco-friendliness, contributing significantly to the development of sustainable energy systems.