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Matériaux pour les batteries Li-AIR : nouvelles approches vers des nano-hétérostructures spinelles/graphène pour électrode à air

Abstract : This research work is focused on the design and characterisation of cobalt based oxides nanospinels anchored onto the surface of reduced graphene oxides (RGO) nanosheet, which will serve as bifunctional catalysts for the new generation lithium-air batteries. Whereas nanospinels are relatively simple to synthesize by conventional colloidal routes as nanoparticles dispersed into an aqueous solution, the synthesis we developed relies on a hydrothermal microwave treatment in the 100°C-200°C range. The main challenges of this nano-heterostructures synthesis was to create the interface between the nanoparticles and the RGO directly during the nanoparticles nucleation. RGO are very efficient microwave absorbers and could then convert microwave irradiation into heat in order to trigger precipitation of the spinel at the surface of the RGO sheet.Starting from Co3O4 as proof-of-concept material, the synthesis protocol has been successfully adapted to address binary oxides by substituting cobalt with first row transition metals such as nickel, manganese or iron. The precipitation of binary and ternary oxides was achievable thanks to a good understanding of the Pourbaix diagrams of all cations to adjust the acido-basic and redox conditions.Finally, the electrocatalytic activity of these supported spinel oxides was measured for both the oxygen reduction and oxygen evolution reactions (ORR and OER). The gap between the ORR and the OER potentials was significantly lowered by the presence of Co3O4 nanoparticles on the RGO, thus assuring the reversibility of this catalytic system, which is to be integrated in future scale-up test.
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https://tel.archives-ouvertes.fr/tel-01949308
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Submitted on : Monday, December 10, 2018 - 1:02:58 AM
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  • HAL Id : tel-01949308, version 1

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Emmanuelle Cazayus-Claverie. Matériaux pour les batteries Li-AIR : nouvelles approches vers des nano-hétérostructures spinelles/graphène pour électrode à air. Chimie-Physique [physics.chem-ph]. Université Pierre et Marie Curie - Paris VI, 2017. Français. ⟨NNT : 2017PA066508⟩. ⟨tel-01949308⟩

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