Research On The Rechargeable Zinc Air Battery With A Molten Eutectic Electrolyte

As a high-energy-density chemical energy storage device,the rechargeable zinc air battery has the advantages of safety,no pollution,low cost,and a wide application prospect in mobile electronic equipment,electric vehicles and other fields.In this paper,with the electrolyte system as the starting point,a new type of rechargeable zinc air battery system using a molten eutectic as electrolyte is designed and constructed.The micro-morphology and composition of the electrode were characterized by SEM,EDS and XRD.The electrochemical performance of the battery was evaluated by cyclic voltammetry,polarization curve test,charge-discharge performance test and rate performance test.The feasibility of the new type of rechargeable molten salt zinc air battery system was studied.The 43.5mol%Li₂CO₃-31.5mol%Na₂CO₃-25mol%K₂CO₃ eutectic with adding NaOH and ZnO was used as electrolyte.A new type of molten salt rechargeable zinc air battery system was constructed successfully using the nickel-based material as air cathode and iron-based material as anode.The battery was charged a t a constant current density of 2.5mA/cm² at 550°C,discharged with a constant resistance of 100Ωto the cut-off voltage of0.8V.The average charge voltage was 1.43 V and the average discharge was 1.04 V in 110 cycles of the battery charge-discharge cycling.The XRD and SEM characterization results show that the uniform N iO nanoparticles catalyzed O ER/ORR were formed in-situ on Ni-based air cathode surface.It was found that the additives have a significant effect on battery performance via an in-depth study on the electrolyte systems with addition of KOH.The addition of KOH could not only reduce significantly the battery charge voltage,but also improve obviously the discharge voltage platform.The average discharge voltage was increased to 1.08 V.The coulombic efficiency of the battery could still reach 91.2%when the discharge rate was up to 7.3.The OER/ORR kinetics was improved using a nickel-based air electrode with a manganese oxide electrocatalysts.The results showed that lithium manganese oxide(Li_1.059Mn_2.118O₄)and nickel oxide（N iO）were in-situ generated on the air electrode surface during the battery charge-discharge cycling.The electrocatalyst could significantly improve the OER/ORR performance of the air cathode.The average coulombic efficiency reaches 89%.The average discharge voltage and voltage efficiency is 1.12 V and 80%,respectively.