Paper published

Title: Electrochemical growth of a corrosion-resistant multi-layer scale to enable an oxygen-evolution inert anode in molten carbonate

Author: Tang, DY (Tang, Diyong); Zheng, KY (Zheng, Kaiyuan); Yin, HY (Yin, Huayi); Mao, XH (Mao, Xuhui); Sadoway, DR (Sadoway, Donald R.); Wang, DH (Wang, Dihua)

Publication: ELECTROCHIMICA ACTA; volume: 279; page: 250-257; DOI: 10.1016/j.electacta.2018.05095; time: July, 2018

Abstract: An in-situ formed three-layered scale consisting of a Cu-rich layer and two oxide layers on the surface of Ni10Cu11Fe alloy enables an inert anode for oxygen evolution reaction in molten Na₂CO₃-K₂CO₃. The outermost layer is mostly NiFe₂O₄, the middle layer mainly consists of NiO, and the innermost is a Curich metal layer. The dense NiFe₂O₄ layer is resistant to molten salts and prevents O₂- diffusing inwards, the middle NiO layer conducts electrons and functions as a buffer layer to increase the mechanical robustness of the whole scale, and the third copper-rich layer could help to slow down the oxidation rate of the alloy. This low-cost inert anode with a multi-layered scale is able to survive for more than 600 h in molten Na₂CO₃-K₂CO₃ electrolysis cell, generating O-2 and thereby enabling a carbon-free electro-metallurgical process.

Key words: temperature oxidation behavior; aluminum electrolysis; nickel ferrite; Ni; Cu; alloy; iron; reduction; kinetics; oxides