Li metal utilization in lithium air rechargeable batteries

Effects of Li amount used for anode on the discharge capacitance of a lithium-air battery were studied in order to investigate the effects of Li usage. On the basis of Ketjenblack air electrode, electrochemical analysis were performed in the voltage range of 4.5–2.0 V. Because the amount of Li limits the overall discharge capacity, the capacity decreases with decreasing the Li amount in the cell. Although only 370 mAh g−1 (gram of air electrode) of capacity was obtained by reducing the Li amount to 0.9 mg, almost 100% of Li can be used for discharge and it is corresponded to 4111 mAh g−1 (gram of Li) with reasonable cycle stability. To confirm the residual amount of Li on anode, ICP measurement was performed after first discharge. Decrease in capacity with cycle number can be assigned to the decreased amount of Li dissolved and this could be related with formation of dendrite and porous Li deposition.

► Reducing the Li metal amount will offer anode effects on the performance. ► Realization of theoretical specific energy density was confirmed on Li-air batteries. ► Low cycle stability was attribute to Li dendrite formation during cycle.