Dual strategies of mild C–F scissoring fluorination and local high-concentration electrolyte to enable reversible Li–Fe–F conversion batteries

Batteries taking conversion-type iron fluorides as energy-dense cathodes provide the possibility for the power electrification of the transportation and aviation industries. However, a safe and low-toxicity synthesis method for fluorides and the design of a compatible electrolyte formula are still challenging. Here, we propose a dual strategy of mild C-F scissoring fluorination and a local high-concentration electrolyte (LHCE) to enable highly reversible Li-Fe-F conversion batteries. A facile and safe scissoring strategy at a low temperature (95 °C) enables the preparation of a carbon-iron fluoride composite with a porous cubic cage-like structure. CF