Electrochemical Performance Of Micro-nanostructure La₂NiO_4+δ In Both SOFC And Li-air Battery

With the decreasing in energy resources and increasing requirement in clean energy,new types of batteries are drawing people’s attention. Among all new types of batteries,solid oxide fuel cells （SOFCs） and Li-air batteries are two types of enormous potential. Thecathode material is the most important components for both SOFCs and Li-air batteries.La₂NiO_4+δhas received significant attention as a mixed conductor material derived fromK2NiF4-type materials for intermediate temperature SOFCs cathode due to its importantadvantages such as high oxygen ionic conductivity, attractive electronic conductivity,moderate temperature expansion coefficient （TEC） and high electrocatalytic activity forboth oxygen reduction reaction （ORR） and oxygen evolution reaction （OER）. In this study,nanostructure La₂NiO_4+δmaterial was prepared by a new way and a series of research of theelectrochemistry performance of La₂NiO_4+δhas been tested. In addition, it was the first timethat La₂NiO_4+δwas used as catalyst in a Li-air battery.La₂NiO_4+δhas been prepared by a template method using F127. The sinteringtemperature for pure compound was successfully decreased to850°C for10h by thismethod. Scanning electron microscopy （SEM） test suggested that the La₂NiO_4+δdisplay ahigh specific surface and fine nanoparticles.Fast sintering method was used for the preparation of La₂NiO_4+δcathode for SOFC.SEM test suggested little increase in particle size and good adherence between cathode andelectrolyte. The La₂NiO_4+δcathode shows a significantly low polarization resistance （0.278Ω cm2） at800°C. An anode-supported single cell with La₂NiO_4+δcathode was fabricated.The maximum power density at800°C reached387mW cm-2.ORR and OER tests were also conducted. The results show that the onset potential was0.6V （vs. RHE） and highest limiting current reached2.66mA cm-2for ORR, while forOER the onset potential was1.48V （vs. RHE） and the highest limiting current reached4.52mA cm-2. A Li-air battery with La₂NiO_4+δcathode was fabricated. The highest dischargecapacity reached3700mA h g-1and retained24cycles with the capacity limited to300mAh g-1. All these results suggest La₂NiO_4+δis a potential Li-air battery cathode material.