Rechargeable Room-Temperature CF_x‑Sodium Battery

Here we demonstrate for the first time that CF_x cathodes show rechargeable capability in sodium ion batteries with an initial discharge capacity of 1061 mAh g^–1 and a reversible discharge capacity of 786 mAh g^–1. The highly reversible electrochemical reactivity of CF_x with Na at room temperature indicates that the decomposition of NaF could be driven by carbon formed during the first discharge. The high reversible capacity made it become a promising cathode material for future rechargeable sodium batteries.