Challenges and possibilities for aqueous battery systems

Fatal casualties resulting from explosions of electric vehicles and energy storage systems equipped with lithium-ion batteries have become increasingly common worldwide. As a result, interest in developing safer and more advanced battery systems has grown. Aqueous batteries are emerging as a promising alternative to lithium-ion batteries, which offer advantages such as low cost, safety, high ionic conductivity, and environmental friendliness. In this Review, we discuss the challenges and recent strategies for various aqueous battery systems that use lithium, zinc, sodium, magnesium, and aluminium ions as carrier ions. We also highlight the three key factors that need the most improvement in these aqueous battery systems: higher operating voltage for the cathode, a more stable metal anode interface, and a larger electrochemical stability window of the electrolyte.