Anode processes on Pt and ceramic anodes in chloride and oxide-chloride melts

Platinum anodes are widely used for metal oxides reduction in LiCl-Li2O, however high-cost and low-corrosion resistance hinder their implementation. NiO-Li2O ceramics is an alternative corrosion resistant anode material. Anode processes on platinum and NiO-Li2O ceramics were studied in (80 mol.%) LiCl-(20mol.%)KCl and (80 mol.%)LiCl-(20 mol.%)KCl-Li2O melts by cyclic voltammetry, potentiostatic and galvanostatic electrolysis. Experiments performed in the LiCl-KCl melt without Li2O illustrate that a Pt anode dissolution causes the Pt2+ ions formation at 3.14 V and 550 degrees C and at 3.04 V and 650 degrees C. A twostage Pt oxidation was observed in the melts with the Li2O at 2.40 divided by 2.43 V, which resulted in the Li2PtO3 formation. Oxygen current efficiency of the Pt anode at 2.8 V and 650 degrees C reached about 96%. The anode process on the NiO-Li2O electrode in the LiCl-KCl melt without Li2O proceeds at the potentials more positive than 3.1 V and results in the electrochemical decomposition of ceramic electrode to NiO and O-2. Oxygen current efficiency on NiO-Li2O is close to 100%. The NiO-Li2O ceramic anode demonstrated good electrochemical characteristics during the galvanostatic electrolysis at 0.25 A/cm(2) for 35 h and may be successfully used for pyrochemical treating of spent nuclear fuel. (C) 2021 Korean Nuclear Society, Published by Elsevier Korea LLC.

Automated summary

Platinum anodes are commonly used for metal oxides reduction, but their high cost and low corrosion resistance limit their application. NiO-Li2O ceramics, as an alternative anode material, show good corrosion resistance. The anode processes and oxygen current efficiency of both platinum and NiO-Li2O ceramics were studied.