Secure and Mild Electrochemical F ₂ Gas Generation from Electrolysis of Tin(II) Fluoride: Investigating the Electrochemical Behavior of the SnF ₂ /CsF‐2.45HF System

In spite of wide‐ranging applications in various fields, the high reactivity and difficulty in storage of elemental fluorine pose significant safety concerns, creating a strong demand for safe, small‐scale, and on‐site generation methods. Herein, the electrochemical behavior of SnF 2 dissolved in CsF‐2.45HF molten salt is investigated as a fluoride source for F 2 gas production by electrolysis of a metal fluoride in view of the use of low valence metal fluorides. SnF 2 exhibits a solubility of 0.31 mol kg −1 , slightly higher than that of CuF 2 previously utilized for this purpose. Cyclic voltammetry and potentiostatic electrolysis show that Sn(II) is reduced to metallic tin without H 2 gas evolution in this medium, indicating its suitability for cathodic metal deposition. On the other hand, F 2 gas production is suppressed on the anodic side, as the generated F 2 readily reacts with Sn(II) to form Cs 2 [Sn(IV)F 6 ]. A system in which the anodic and cathodic compartments are separated by a solid fluoride‐ion conductor is proposed to address the issue of Sn oxidation. This study contributes to the advancement of compact and secure electrochemical systems for the practical handling of F 2 gas under mild conditions.