This paper presents the integration of three advanced materials, combined through an innovative processing technique, to develop sustainable energy storage devices, specifically, eco-friendly, lightweight, transparent, and flexible sodium-ion batteries operating entirely in aqueous media. The final device configuration features a cathode composed of a cobalt hexacyanoferrate/carbon nanotube nanocomposite (CoHCF/CNTs), an anode based on a nanoarchitecture of reduced graphene oxide, molybdenum disulfide, and copper oxide nanoparticles (rGO/Cu_xO/MoS₂), and a polyvinyl alcohol/sodium chloride/boric acid hydrogel (PVA/NaCl/H₃BO₃) serving as both electrolyte and separator. Using either rigid (ITO/glass) or flexible (ITO/polyethylene terephthalate, PET) transparent electrodes, we fabricated transparent battery devices in rigid and flexible configurations. These were characterized using scanning electron microscopy and Raman spectroscopy, including in operando methods. The rigid device delivered a specific capacity of 73 mA h g⁻¹ at 0.5 A g⁻¹, while the flexible configuration achieved at least 90 mA h g⁻¹. It also demonstrated excellent cycling stability, retaining 85% of its capacity after 2000 cycles at 2 A g⁻¹, with a coulombic efficiency exceeding 82%. The battery achieved an energy density of 43.1 W h kg⁻¹ at a power density of 1.7 kW kg⁻¹. As a proof of concept, the device was used to power an LED by connecting multiple charged units.