Cobalt ion-doped polyvinyl alcohol: A promising multivalent polymer electrolyte system for aluminium - Air battery application

Abstract

Polyvinyl alcohol (PVA) is utilized in the preparation of multivalent polymer electrolytes by solution casting technique. Films with varying salt content (0–6 mMol CoCl 2 /g polymer) are obtained by mixing the required quantities of cobalt chloride (CoCl 2 ) and polymer solutions and allowing the mixture to dry into a free standing film in a Petri dish. The electrical, dielectric, and ion transport properties of the films are characterized using electrochemical impedance spectroscopy (EIS). The results show that CoCl 2 doping enhanced the conductivity of PVA from 6.1 x10 −11 S/cm in the pristine state to ∼10 −3 S/cm at 6 mmol/g representing an 8 orders of magnitude rise in conductivity. The existence of polymer-salt interactions and their impact on the microstructure of the films are examined using Fourier transform infrared (FTIR), and X-ray diffraction (XRD) spectroscopy, and scanning electron microscopy (SEM). The films’ suitability for application in energy conversion/storage devices is demonstrated with the assembly of electrochemical cells with configuration Al/PVA_CoCl 2 /C that show terminal voltages of 0.92–1.1 V and amperages of 1.4–946 μA.