One-step synthesis of highly reduced graphene hydrogels for high power supercapacitor applications

Harish Banda (1) , David Aradilla (2) , Anass A Benayad (3) , Yves Chenavier (4) , Barbara Daffos (5, 6) , Lionel Dubois (1) , Florence Duclairoir (1)

1 SYMMES - SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé
2 PCI - Polymères Conducteurs Ioniques
3 LITEN - Laboratoire d'Innovation pour les Technologies des Energies Nouvelles et les nanomatériaux
4 RICC - Reconnaissance Ionique et Chimie de Coordination
5 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux
6 RS2E - Réseau sur le stockage électrochimique de l'énergie

Graphene hydrogels with high electrical conductivity were prepared by a one-step process using hydrazine hydrate as gel assembly agent (GH-HD). Conventional two-step process of gel formation and further reduction to prepare highly conducting gels was replaced by a single step involving equivalent amount of hydrazine. Optimized graphene oxide concentration was established to facilitate such monolith formation. Extensive characterization and control studies enabled understanding of the material properties and gel formation mechanism. The synthesized gel shows a high electrical conductivity of 1141 S/m. The supercapacitor based on GH-HD delivers a high specific capacitance of 190 F/g at a current density of 0.5 A/g and 123 F/g at very high current density of 100 A/g. Furthermore, excellent power capability and cyclic stability were also observed. 3D macroporous morphology of GH-HD makes it ideal for high rate supercapacitor applications.

Mots clés: Supercapacitors; Graphene hydrogels; Aqueous electrolyte

Domaines: Matériaux; Energie électrique; Environnement et Société

Harish Banda, David Aradilla, Anass A Benayad, Yves Chenavier, Barbara Daffos, et al.. One-step synthesis of highly reduced graphene hydrogels for high power supercapacitor applications. Journal of Power Sources, 2017, 360, pp.538-547. ⟨10.1016/j.jpowsour.2017.06.033⟩. ⟨hal-02025387⟩