Degradation of LiCoO2in aqueous lithium-air batteries

Abstract

The degradation behaviour of aqueous rechargeable lithium cobalt oxide–air batteries in 5 M 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 1.15/0.97 V are proven to produce good reversibility. The small separation of the peaks is proportionally consistent with the Li+ diffusion coefficients of 2.82 × 10−7 cm2 s−1 (anodic) and 1.76 × 10−7 cm2 s−1 (cathodic). The lithium cobalt oxide–air batteries have a higher initial specific discharge capacity of 114.35 mA h 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 © 2016 John Wiley & Sons, Ltd.