NiFe2O4-based cermet inert anode in CaCl2-based molten salts

Stable inert anode presents a promising alternative to active graphite anodes in molten salt electrolysis, offering a significant reduction in CO 2 emissions. However, developing such anodes remains a significant challenge. In this study, a novel metal-spinel cermet inert anode for use in CaCl 2 -based molten salts was introduced. Three spinel materials—NiFe 2 O 4 , MgFe 2 O 4 , and MgAl 2 O 4 —were synthesized and their electrochemical properties were compared. It was observed that NiFe 2 O 4 emerged as the most effective spinel ceramic. Subsequently, 20 wt%(50Cu-Ni)- x NiO-NiFe 2 O 4 ( x  = 0, 10, 20) were prepared and evaluated. Furthermore, according to polarization behavior, density, and conductivity, the 20 wt%(50Cu-Ni)-10NiO-NiFe 2 O 4 anode exhibited superior performance in CaCl 2 -CaO molten salt, which outperformed conventional SnO 2 inert anodes. Its corrosion rate was measured at only 1.25 × 10 −3  g cm −2  h −1 over 20 h of electrolysis. Additionally, carbon spheres were successfully prepared using the 20 wt%(50Cu-Ni)-10NiO-NiFe 2 O 4 cermet anode in CaCl 2 -5 wt% CaCO 3 molten salt, thereby achieving a current efficiency of ∼85.5 %. The NiFe 2 O 4 -based cermet exhibited significant potential as an inert anode for sustainable metallurgical processes.