Carbon fluorides for rechargeable batteries

For almost half a century, lithium/carbon fluorides (Li/CFx) batteries have been considered irreversible in liquid electrolyte, but they still have attractive features such as a flat discharge plateau, a wide operating temperature window, and outstanding shelf life. Such benefits have spurred interest in developing rechargeable CFx batteries. To date, different metal/CFx batteries have been developed, including Li/CFx, Na/CFx, Mg/CFx, Al/CFx, and K/CFx batteries. This review introduces progress made in rechargeable metal/CFx batteries, as well as their reaction mechanisms. Moreover, the design rules for rechargeable metal/CFx batteries are proposed based on the relationships between CFx materials, electrode structure, electrolytes, and electrochemical performance. This review offers guidance for developing advanced rechargeable CFx batteries, and inspires further exploration for batteries with higher energy density and cycle life.