High stable Li-air battery cells by using {PEO} and {PVDF} additives in the TEGDME/LiPF6 electrolytes

By Uluda?, A. Akbulut; Tokur, M.; Algul, H.; Cetinkaya, T.; Uysal, M.; Akbulut, H.
Published in International Journal of Hydrogen Energy NULL 2016

Abstract

Abstract An ether based electrolyte containing TEGDME/LiPF6 was optimized, which possessed low viscosity and high ionic conductivity, under dry argon atmosphere in a glove box. In order to prevent air breathing cathode clogging by lithium oxide and provide stability of Li metal anode, different types in varying quantities of polymeric additives such as {PEO} and {PVDF} were added into TEGDME/LiPF6. These additives are thought to promote the dissolution of lithium peroxide precipitates formed in course of discharge process and protect the anode. Graphene/?-MnO2 nanocomposite air breathing structure coated on nickel mesh was used as cathode. A lithium disk was used as anode while glass fiber was used as the separator in ECC-Air test cells. The cells were cyclically tested using 0.1 mA/cm2 current density over a voltage range of 2.15-4.25 V. Electrochemical impedance spectroscopy (EIS) measurements was applied to investigate the effect of the polymeric additives on the resistivity of the electrolyte. Results revealed that polymer contained electrolyte structures with {PVDF} addition provided not only good discharge capacity but also excellent stability. After the electrochemical cycling test, the morphologies of the cathodes were analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis, and Raman spectroscopy to determine the reaction products.

Read » Back