The degradation behaviour of aqueous rechargeable lithium cobalt oxide- air batteries in 5M LiNO3 aqueous solution is observed by electrochemical characterizations. At lower scan rates of cyclic voltammetry, the three pairs of redox peaks at ESCE = 0.79/0.67, 0.89/0.85 and 1.15/0.97V are proven to produce good reversibility. The small separation of the peaks is proportionally consistent with the Li+ diffusion coefficients of 2.82 x 10(-7) cm(2) s(-1) (anodic) and 1.76 x 10(-7) cm(2) s(-1) (cathodic). The lithium cobalt oxide- air batteries have a higher initial specific discharge capacity of 114.35mAh g(-1), which fades to 83% (after the first 10 cycles) and 52% (after 50 cycles). As the specific discharge capacity decreases, the resistance increases. The dissolution of Li+ is mainly attributed to these degradations. Further analyses of the batteries' degradation are performed by morphological and structural characterizations of the cathode material. Copyright (C) 2016 John Wiley & Sons, Ltd.