Generation of Elemental Fluorine through the Electrolysis of Copper Difluoride at Room Temperature

The safe generation of F₂ gas at room temperature by using simple cell configurations has been the "holy grail" of fluorine research for centuries. Thus, to address this issue, we report generation of F₂ gas through the electrolysis of CuF₂ in a CsF-2.45HF molten salt without the evolution of H₂ gas. The CuF₂ is selected through a series of thermodynamic and kinetic assessments of possible metal fluorides. Anode assessments on graphite and glass-like carbon demonstrate the effect of the absence of the anode during generation of F₂ gas owing to stabilized operations at room temperature. Although the Ni anode dissolves during electrolysis in the conventional medium-temperature cell, herein, it facilitates stable electrolysis over 100 h, achieving an F₂ gas purity of over 99 % with the potential to operate using one-compartment electrolysis. This work presents a safe and propitious method for the generation of high-purity F₂ gas for small-scale lab and industrial applications.