Measurement of Gibbs energies of formation of CoF 2 and MnF 2 using a new composite dispersed solid electrolyte

Abstract. Gibbs energies of formation of CoF2 and MnF 2 have been measured in the temperature range from 700 to l t00 K using Al203-dispersed CaF 2 solid electrolyte and Ni + NiF2 as the reference electrode. The dispersed solid electrolyte has higher conductivity than pure CaF2 thus permitting accurate measurements at lower temperatures. However, to prevent reaction between A120 3 in the solid electrolyte and NiF2 (or CoF2) at the electrode, the dispersed solid electrolyte was coated with pure CaF2, thus creati.ng a composite structure. The free energies of formation of CoF 2 and MnF 2 are (+ 1700)J tool-l;