Development of a Solid-State Magnesium-Persulfate Based Rechargeable Battery

Abstract

Several coin cells with cathode materials ranging from stainless steel, magnesium persulfate, and magnesium persulfate/reduced graphene oxide (rGO), as well as a novel electrolyte, were fabricated and assembled. They were characterized using scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDX), and voltammetry to determine surface morphology, elemental composition, and electrochemical characteristics, respectively. The amount of the additive, rGO, was verified by analyzing the current response after 10 consecutive scans via cyclic voltammetry. The optimum amount which only had a 19% decrease from cycle 2 to cycle 9 was from the cathode electrode which had 4mg rGO. However, galvanostatic charge-discharge measurements showed that the coin cells had no ability to hold the charge after cycling. The coin cell which contained the optimized cathode electrode was dismantled for further surface and elemental analysis. After a scan, some of the cathode material was converted to its reduction product magnesium sulfate (MgSO4) and failed to revert back to its original persulfate form which signified irreversibility. Contaminants were found on the surface of the anode and corrosion were observed on the surface of the current collector which denotes instability of the components with the chosen electrolyte. The reactivity of the components with each other was also predicted by previous studies.