Enable Rechargeable Carbon Fluoride Batteries with Unprecedented High Rate and Long Life by Oxygen Doping and Electrolyte Formulation

Abstract

Here, a rechargeable carbon fluoride battery is demonstrated with unprecedented high rate and long life by oxygen doping and electrolyte formulation. The introductions of Mn2+–O catalyst and porous structure during the oxidation process of CFx cathode can promote the splitting of Li–F during charging. By further modulating the electrolyte with triphenylantimony chloride (TSbCl) as anion acceptor and CsF as product modulator, the more readily dissociable CsLiF2 product instead of LiF is preferentially formed, and the TSbCl‐salt protection interface is constructed to confine Li–F based products and reduce fluoride loss at cathode side. These effects endow Li‐CFx batteries with durable reversible conversion reaction (for at least 600 cycles), ultrahigh rate performance (e.g., 364 mAh g−1 at 20 A g−1) and low charging plateau voltage down to 3.2 V. The cathode exhibits the maximum power density of 38342 W kg−1 and energy density of 1012 Wh kg−1. Furthermore, this Li‐CFx system demonstrates the promising prospects for applications in view of its low temperature operation (e.g., 280 mAh g−1 at −20 °C), low self‐discharge ability, large‐scale pouch cell fabrication and high cathode loading (5–6 mg cm−2), enabling it to move beyond previous role as primary battery and into new role as fast‐charging rechargeable battery with high energy density.