Synthesis and electrochemical analysis of Nb2O5-TiO2/H-rGO sandwich type layered architecture electrode for supercapacitor application

- Relatively high surface area (738 m2/g) rGO was by modified Hummer's method.
- Uniform sized Nb2O5 doped TiO2 nanorods synthesized by hydrothermal method.
- Sandwich type layer-by-layer deposition was achieved by electrophoretic process.
- Sandwich layered electrode showed a specific capacitance of 889 F/g.
- Sandwich type electrode showed better performance than usual layered electrode.

A novel Nb2O5-TiO2/H-rGO nanocomposite with an alternative material formed by layer-by-layer deposition was produced using a simple and versatile electrophoretic deposition process for supercapacitor applications. The assembled alternative material layer-by-layer deposited (AMLLD) electrode architecture facilitated good electrolyte diffusion and exhibited a high specific capacitance with a high energy density. Before the deposition process, Nb2O5-TiO2 and high surface area reduced graphene oxide (H-rGO) nanomaterials were synthesized by a hydrothermally assisted ion exchange technique and modified Hummer's method, respectively. The H-rGO/Nb2O5-TiO2/H-rGO sandwich layer configuration exhibited a high specific capacitance of 889 F/g and a high energy density of 123.48 Wh/kg at a current density of 5 A/g in 0.5 M Na2SO4 electrolyte. On the other hand, the non-sandwich amalgamated Nb2O5-TiO2/H-rGO nanocomposite-layered electrode showed a specific capacitance of 683 F/g and an energy density of 94.87 Wh/kg. In addition, the AMLLD sandwich electrode showed good cycling stability; ∼95% of the initial specific capacitance was retained after 1000 cycles. This facile and scalable fabrication process provides a new electrode design for high energy storage advancements.

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