Effect of thermal treatment on the charge storage properties of graphene oxide/12-tungstophosphoric acid nanocomposite

- The successful anchoring and high dispersion of WPA on GO matrix was achieved.
- The effect of annealing in Ar on GO/WPA charge storage properties was examined.
- The nature of GO-WPA interaction was examined and discussed.
- The synergistic effects of GO and WPA improved both capacitance and operating voltage.

The influence of thermal treatment in an inert atmosphere on the charge storage properties of graphene oxide (GO)/12-tungstophosphoric acid (WPA) nanocomposite was examined. The transmission electron microscopy analysis revealed high dispersion of WPA on GO matrix, while the surface analysis showed thermal activation of structural changes of WPA and desorption of oxygen functional groups from GO and GO/WPA nanocomposite. Initial GO/WPA nanocomposite had approximately two times higher capacitance compared to initial GO. The thermal treatment of initial GO and GO/WPA to 500 °C induced twofold increase of capacitance of GO and 40% increase of GO/WPA, accompanied with significant increase of operating voltage compared to GO (for 300 mV). Above 500 °C, a decrease of capacitance of both GO and GO/WPA was observed. The results suggest that understanding of structural changes of components and their interaction is crucial for improvement of electrochemical properties of considered composite.

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