Layer-by-layer self-assembly of ultrathin multilayer films composed of magnetite/reduced graphene oxide bilayers for supercapacitor application

•Fabrication of LBL assembled Fe3O4/RGO ultrathin multilayer films with well-controlled architectures and nm thickness.•The Fe3O4/RGO film provided excellent capacitive performance.•Development of micro-size electrodes for energy storage and sensors applications.

This article describes electrochemical properties of layer-by-layer self-assembled multilayer films composed of magnetite nanoparticle (Fe3O4 NP) and chemically reduced graphene oxide (RGO) for supercapacitor application. The thickness of the Fe3O4/GO bilayer was determined by optical ellipsometry to be 6.53 ± 0.17 nm, which agreed well with the sum of the independently measured thickness for each Fe3O4 (5.61 ± 0.14 nm) and GO (0.91 ± 0.1 nm) layer component. Each layer was found to be deposited uniformly and regularly. Fe3O4/RGO multilayer film was obtained by reducing a Fe3O4/GO film using hydrazine. The multilayer film yielded a minimum resistance of 1.0 × 104 Ω/sq (2.8 S/cm) for a film with approximately 50 bilayers. The electrodes fabricated from 30 Fe3O4/RGO bilayers exhibited excellent capacitive performances with a maximum specific gravimetric capacitance (151 F/g) at a current density of 0.9 A/g.

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