Influence of nano zirconia on NiAl anodes for molten carbonate fuel cell: Characterization, cell tests and post-analysis

Anode materials in Molten Carbonate Fuel Cells should have high creep resistance and good mechanical behavior to endure in high temperature-corrosive environments. In this work, zirconia nanoparticles (1–10% wt.) are added to NiAl anodes in order to investigate their effects on mechanical properties and single cell performances. Results show that nanoparticles strongly adhere to metal particles and bending strength increases from 6.08 to 11.33 kg_f cm⁻² while creep strain is reduced from 7.55% to 3.25%. In the case of the anode with ZrO₂ 3% wt., the stable and high output voltage of 0.81 V at 150 mA cm⁻² is a promising result, compared to the literature. In addition, the solid contact angles between melted electrolyte and anode, for the NiAl reference sample and the ZrO₂ 3% wt. are 37.6° and 17°, respectively, showing the improved wettability of the modified anode. However, it seems to be a limit to the effective zirconia content as the contact angle of the anode with ZrO₂ 10% wt. is 58.1°, which indicates a low wetting ability. When zirconia content is too high, single cells have low performances due to high internal resistance and porosity reduction. The formation of a zirconate phase also occurs during operations.