Rechargeable aqueous lithium-air batteries with an auxiliary electrode for the oxygen evolution

A rechargeable aqueous lithium-air cell with a third auxiliary electrode for the oxygen evolution reaction was developed. The cell consists of a lithium metal anode, a lithium conducting solid electrolyte of Li sub(1+x+y)Al sub(x)(Ti,Ge) sub(2- x)Si sub(y)P sub(3-y)O sub(12), a carbon black oxygen reduction air electrode, a RuO sub(2) oxygen evolution electrode, and a saturated aqueous solution of LiOH with 10 M LiCl. The cell was successfully operated for several cycles at 0.64 mA cm super(-2) and 25 [degrees]C under air, where the capacity of air electrode was 2000 mAh (ProQuest: Formulae and/or non-USASCII text omitted). The cell performance was degraded gradually by cycling under open air. The degradation was reduced under CO sub(2)-free air and pure oxygen. The specific energy density was calculated to be 810 Wh kg super(-1) from the weight of water, lithium, oxygen, and carbon in the air electrode.