Electrochemical Properties of Large-Discharge-Capacity Air Electrodes with Nickel Foam Sheet Support for Lithium Air Secondary Batteries

Abstract

Air electrodes with millimeter-order thickness for lithium air secondary batteries were prepared by loading electrode materials containing carbon and electrocatalyst into a single-layer nickel foam sheet or stacking three nickel-foam sheets loaded with the electrode materials. Discharge properties of the lithium air secondary battery cells incorporating these air electrodes were examined in 1 mol/l LiTFSA/TEGDME under a pure oxygen flow. The cell incorporating the air electrode with carbon loaded into the three-layer stack of nickel-foam sheets with total thickness of 3 mm showed a rather large discharge capacity of about 80 mAh/cm² compared to about 30 mAh/cm² for the cell with a carbon-only air electrode incorporating a single nickel-foam sheet with 3-mm thickness. The cell incorporating an air electrode loaded with Pt₁₀Ru₉₀ electrocatalyst could be cycled under the condition of large cut-off capacities of 10 mAh/cm² at current density of 0.2 mA/cm².