Recent advances in multifunctional generalized local high-concentration electrolytes for high-efficiency alkali metal batteries

Alkali metal batteries (AMB, A=Li, Na, K) are considered to be the most promising energy storage devices to achieve high energy density. As the blood of the battery, to realize stable energy storage in high-energy-density alkali metal batteries, the electrolyte needs to be properly designed. Over the past three decades, electrolytes have evolved from regular concentration electrolytes, ionic liquid electrolytes, and high-concentration electrolytes to localized ionic liquid electrolytes, localized high-concentration electrolytes, and quasi-localized high concentration electrolytes. Due to the wide variety of alkali metal battery electrolytes, this review first proposes the concept of generalized local high-concentration electrolyte (g-LHCE) based on the characteristics of the solvation structure, supplements the descriptor values of different solvents, and summarizes the design principles of g-LHCE. Then the progress of g-LHCE in recent years in terms of high voltage, solid-liquid interface, low temperature, and nonflammability is summarized. Finally, the future development of g-LHCE is prospected. High-entropy generalized local high-concentration electrolytes and local high-concentration aqueous electrolytes will become important research directions for advanced electrolyte design in the field of high energy density and high power density alkali metal batteries.

Automated summary

Alkali metal batteries are considered the most promising energy storage devices for achieving high energy density. This review focuses on the design of electrolytes for stable energy storage in these batteries. The concept of generalized local high-concentration electrolyte (g-LHCE) is proposed, and its design principles are summarized. The progress and future prospects of g-LHCE in terms of high voltage, solid-liquid interface, low temperature, and nonflammability are discussed.