Ni-Fe-Ce(Mn,Fe)O₂ cermet anode for rechargeable Fe-Air battery using LaGaO₃ oxide ion conductor as electrolyte

There is a strong demand for the development of a large capacity rechargeable battery in various fields. Recently, we proposed the combination of solid oxide fuel cell technology with Fe-air battery concepts using H ₂/H₂O as a redox mediator and a LaGaO₃-based oxide as an electrolyte. Because large internal resistance and large degradation during charge and discharge cycles were observed on the anode, there is a strong demand for improvements in discharge potential and cycle stability. This study investigates the use of a cermet anode consisting of a Ni-Fe alloy combined with an oxide ion conductor. It was observed that by using a cermet anode of Ni-Fe combined with Ce_0.6Mn_0.3Fe _0.1O₂ (CMF), the observed capacity of the cell was improved to 1163 mAh g^-1 Fe^-1 at 10 mA cm^-2 and 873 K. This is about 97% of the theoretical capacity by assuming the formation of Fe₃O₄ (1200 mAh g^-1 Fe^-1). Cycle stability of the cell was also considerably improved with the use of a Ni-Fe-CMF anode compared to a Ni-Fe anode because of the suppressed aggregation provided by the mixing of Ni with CMF.