Preparation Of Metal Oxide Cathode Materials And Regulation Of Battery Performance For Rechargeable Iron Molten Air Battery

Iron molten air battery have the advantages of low cost,high energy density,and environmental friendliness.It has favorable application prospects in the fields of smart grid and energy storage.However,there are still many problems in iron molten air battey,including low oxygen mass transfer rate,poor resistance to polarization,and poor stability of the catalyst in high-temperature molten salt.In this paper,a La₂O₃-Ni Mn O₃ composite cathode catalyst was prepared,and a new molten electrolyte system was constructed by adding Cs₂CO₃ to Li_0.87Na_0.63K_0.50CO₃ system.The catalysts and electrode products were characterized by SEM,EDS and XRD.Effects of electrocatalyst and Cs₂CO₃ on battery performance were studied by CV,LSV,charge/discharge polarization,and charge/discharge test.A new iron molten air battery was constructed using La₂O₃-Ni Mn O₃ composite as the cathode catalyst and Li_0.87Na_0.63K_0.50CO₃ with adding Cs₂CO₃ as the electrolyte.The electrochemical performance of the iron molten air battery was investigated.The Ni Mn O₃-La₂O₃ composite is synthesized on porous nickel foam substrates by a hydrothermal method and used as a cathode catalyst for the iron molten air battery.The as-obtained Ni Mn O₃ exhibits a regular and closely stacked cuboid structure which was formed by nanoparticles with a diameter of 2-5 nm.La₂O₃ nanoparticles were evenly distributed around the Ni Mn O₃ cuboid.The results show that the Ni Mn O₃-La₂O₃composite has superior oxygen evolution reaction?OER?/oxygen reduction reaction?ORR?activity and excellent stability and durability.The iron molten air battery with Ni Mn O₃-La₂O₃ composite cycles stably over 250cycles with the highest Coulombic efficiency of close to 100%and the average discharge potential of 1.12 V and a charge-discharge voltage difference of about 0.29 V at 500°C in the air.A new molten electrolyte system was constructed by adding Cs₂CO₃ to the original carbonate electrolyte Li_0.87Na_0.63K_0.50CO₃.The electrochemical performance of iron-air batteries was investigated by using the lithiated Ni O as cathode catalyst.The results show that the electrochemical performance of the battery was gradually improved with increase of Cs₂CO₃ amount.The electrolyte composition of Cs_0.28Li_0.75Na_0.55K_0.42CO₃exhibits the best electrochemical performance.Higher Cs₂CO₃ concentration should cause an increase of the electrolyte viscosity,being not conducive to mass transfer.The introduction of Cs₂CO₃significantly improves the solubility of oxygen in the electrolyte,enhances the contact of oxygen with electrocatalyst at the three-phase interface,leading to improving the mass transfer rate and ORR activity.The battery can be stably operated at 500°C for about 23000 minutes?600 cycles?with a discharge average voltage of 1.14 V and an average coulomb efficiency of above 95%.The voltage efficiency is up to 80.3%,and the charge-discharge voltage difference is less than 0.29 V.A new iron molten air battery was constructed using La₂O₃-Ni Mn O₃ composite as the cathode catalyst and Li_0.87Na_0.63K_0.50CO₃ with adding Cs₂CO₃ as the electrolyte.This battery system displays excellent anti-polarization performance and ultra electrochemical performance.The battery exhibits a coulomb efficiency of 99%in 200 charge-discharge cycles with a voltage efficiency of 81.5%.The average discharge average voltage is greater than 1.17 V,and a charge-discharge voltage difference is less than 0.25 V.