Transitioning From Primary to Rechargeable Li/CF x Batteries: Mechanistic Insights and Design Strategies

ABSTRACT Lithium/carbon fluoride (Li/CF x ) batteries represent a class of advanced primary batteries characterized by exceptional energy density, broad operational temperature range, and ultra‐long storage life. However, their practical deployment is fundamentally constrained by the inherent irreversibility of the conversion electrochemistry. During discharge, strong covalent C─F bonds undergo cleavage, yielding carbon and insulating LiF with high dissociation energy, which severely impedes the reverse charging process and limits the development of rechargeable Li/CF x systems. In this review, we systematically examine the electrochemical mechanisms and key challenges associated with reversible Li/CF x batteries, with emphasis on the critical roles of CF x cathodes and electrolytes. We then comprehensively summarize representative design strategies, including semi‐ionic C─F bond engineering, nanostructured CF x design, catalyst incorporation, electrolyte additive optimization, solvent engineering, and solid‐state electrolyte utilization. Related rechargeable alkali metal fluoride‐carbon systems are also discussed to provide comparative insights. Finally, we outline the remaining critical obstacles and propose future research directions, aiming to offer reliable guidance for the rational design of high‐performance rechargeable Li/CF x batteries.