Characterization and electrochemical performance of CeO2 and Eu-doped CeO2 films as a manganese redox flow battery component

Abstract Hexagonal CeO 2 and Eu-doped CeO 2 nanoparticles were obtained using a facile microwave-hydrothermal method under mild conditions and their application towards manganese redox flow battery component were studied. The structural properties were studied by X-ray diffraction and indicate that samples present a fluorite structure. Raman spectroscopy shows Eu 3+ ions substitute Ce 4+ and generate oxygen vacancies. Electrochemical properties of pure and Eu-doped CeO 2 films deposited at graphite substrates investigated by cyclic voltammetry and galvanostatic charge–discharge indicate that dopant concentration affects the electrochemical properties of CeO 2 . The increase in the reversibility redox of electrochemical systems observed is attributed to coexistence of Ce 4+ /Ce 3+ redox couple confirmed by XPS. Charge–discharge tests display coulombic and voltage efficiency values of above 80% and 90%, respectively. The obtained specific capacity for Ce 0.99 Eu 0.01 O 2 (372.49 mAh/g) and pure oxide (334.84 mAh/g) indicates that both samples are promising for application in Mn-batteries.