Enhancing Ni anode performance via Gd2O3 addition in molten carbonate-type direct carbon fuel cell

Abstract Recently, there is a consensus that a limited performance in direct carbon fuel cell (DCFC) using molten carbonate electrolyte is caused by the limited triple phase boundaries (TPB) formation. In order to solve this problem, we added Gd 2 O 3, a well-known lanthanide oxide material for the improvement of wettability in the Ni anode. As a result, it was clearly shown that the voltage drop level and charge transfer resistance was decreased, and therefore the peak power density was increased by almost two times that of solely Ni anode to reach up to 106.7 mW/cm 2 with carbon black and 114.1 mW/cm 2 with actual coal fuel. The increased wettability led to the improvement of triple phase boundary (TPB) formation and consequently the enhancement of DCFC performance. While the wettability was increased with oxide content in Ni anode, the proportion of Ni at the surface of anode and the electronic conductivity was gradually decreased. With this reason, the peak power density showed the volcano type change with the amount of Gd 2 O 3 addition. Finally, it was revealed that the optimum composition for the anode was Ni:Gd 2 O 3  = 1:5 in weight ratio.