Surface modified CFx cathode material for ultrafast discharge and high energy density†
Li/CFx primary possesses the highest energy density of 2180 W h kg−1 among all primary lithium batteries. However, a key limitation for the utility of this type of battery is in its poor rate capability because the cathode material, CFx, is an intrinsically poor electronic conductor. Here, we report on our development of a controlled process of surface de-fluorination under mild hydrothermal conditions to modify the highly fluorinated CFx. The modified CFx, consisting of an in situ generated shell component of F-graphene layers, possesses good electronic conductivity and removes the transporting barrier for lithium ions, yielding a high-capacity performance and an excellent rate-capability. Indeed, a capacity of 500 mA h g−1 and a maximum power density of 44 800 W kg−1 can be realized at the ultrafast rate of 30 C (24 A g−1), which is over one order of magnitude higher than that of the state-of-the-art primary lithium-ion batteries.