Toward Promising Cathode Catalysts for Nonlithium Metal–Oxygen Batteries

The success of Li–air/O2 batteries has brought extensive attention to the development of various promising non-Li metal–O2 batteries, such as Zn–O2, Al–O2, Mg–O2 batteries, etc., which have exhibited unique advantages, such as low production cost, high energy density, and much enhanced safety. The versatile non-Li metal–O2 batteries provide a better opportunity for meeting the practical requirements for sustainable energy supplies in various applications. A high-performance cathode in non-Li metal–O2 batteries that can effectively trigger both oxygen reduction and evolution reactions and thus boost the overall battery performance is of great research interest. In this article, a comprehensive review on the development of Li-free metal–O2 batteries and particularly focusing on the oxygen catalytic cathodes for both primary and secondary non-Li metal–O2 batteries is carefully performed. The current challenges and potential solutions are also outlined and proposed. Through carefully selecting and rationally designing promising catalytic cathodes, a series of non-Li metal–oxygen batteries toward practical energy storage applications are highly anticipated.