Generation of elemental fluorine through the electrolysis of copper difluoride at room temperature.

The safe generation of F2 gas at room temperature using simple cell configurations has been the 'holy grail' of fluorine research for centuries. Thus, to address this issue, we report F2 gas generation 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 absence of the anode effect during F2 gas generation due to stabilized operations at room temperature. Although Ni anode dissolves during electrolysis in the conventional medium-temperature cell, herein, it facilitates stable electrolysis over 100 h, achieving the F2 gas purity over 99 % with potential operation using one-compartment electrolysis. This work presents a safe and propitious mechanism for high-purity fluorine gas generation for small-scale lab and industrial applications.