Electrolyte Design Strategies for High‐Energy‐Density Li/Na/K‐Metal Batteries Toward Grid‐Scale Energy Storage: From Liquid to Solid

The growing demand for grid‐scale battery energy storage systems (BESSs) has prompted researchers to turn their attention to alkali metal anodes (particularly lithium, sodium, and potassium), which feature higher capacity and lower potential. As a new system, the design of electrolytes has become a focus of research. However, most studies on alkali metal batteries remain confined to systems with thin cathodes and excess alkali metals, making them difficult to translate into practical applications. This review outlines the current requirements and challenges for grid‐scale battery energy storage systems. By clarifying the definitions of the N/P ratios and the relationship between full/half cells, it focuses on the loading of the cathode and the amount of electrolyte. In addition, this review systematically compiles the latest research advances and design strategies in electrolyte technology (ranging from liquid to solid states). By comparing liquid and solid electrolytes, it clarifies the required properties and characteristics of liquid–solid electrolytes in practical battery systems. Finally, it highlights critical challenges and potential future research directions in the field, aiming to facilitate the practical application of Li/Na/K‐metal batteries in next‐generation grid‐scale energy storage systems.