*Important notice: This news reports on an unedited version of an accepted paper and is awaiting final editing. Therefore, the paper should not be regarded as conclusive or treated as established information.
Researchers have developed a moisture-driven electric generator (MEG) constructed entirely from waste biomass and recycled materials that converts electrical energy from ambient humidity for sustainable, low-power applications.
Study: Sustainable moisture-driven electricity generation using waste materials. Image Credit: Dolores M. Harvey/Shutterstock.com
Moisture-Driven Energy Context
Atmospheric moisture represents a promising abundant and renewable resource for sustainable energy harvesting.
Techniques that convert ambient humidity into electricity have recently gathered interest due to their potential to provide flexible, low-power energy sources without reliance on traditional fuel or batteries.
Existing systems, however, are often limited by high material costs, complex fabrication, low electrical output, and the need for sealing to maintain moisture gradients. This restricts flexibility and scalability.
Moreover, many moisture-driven generators produce voltages below 0.6 V, insufficient for direct integration into low-power electronics and wearable devices. Addressing these limitations, this research develops a moisture-driven electric generator that uses widely available waste biomass and recycled materials.
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Composite Design and Fabrication
The electric generator was engineered by designing a composite structure composed primarily of wild sugarcane fibers (Saccharum spontaneum) and cellulose acetate fibers extracted from recycled cigarette butts.
These two waste-derived fibrous materials were selected for their complementary roles: sugarcane fibers provide strong water affinity due to polar functional groups, enhancing moisture uptake, while cigarette fibers offer a porous matrix facilitating ionic transport and mechanical stability.
The fibers underwent extensive cleaning and chemical treatments to remove contaminants and improve functionality, including washing with hot water, bleaching with sodium hydroxide and hydrogen peroxide, and acid immersion for purification. The composite was constructed in a layered, planar quadrilateral form, where saline solution (sea salt dissolved in water) was sprayed between layers to supply hygroscopic salts necessary for ion dissociation.
Polyvinyl acetate resin was applied as a binder to maintain integrity. To enable charge collection, the composite surface was coated with a carbon black and manganese dioxide mixture derived from e-waste dry cell batteries, enhancing moisture absorption and ion transport. Ultra-flexible aluminum foil, also repurposed from e-waste, served as the negative current collector on the opposite side, secured using the same resin adhesive.
The structural design aimed to optimize directional ion migration and maintain an internal moisture gradient under ambient humidity conditions. Electrical output was characterized by measuring open-circuit voltage and short-circuit current within a humidity-controlled chamber, with relative humidity regulated using saturated salt solutions.
Ionic transport and moisture absorption behaviors were analyzed through scanning electron microscopy, energy-dispersive X-ray spectroscopy, and other physicochemical methods. Device flexibility and scalability were tested by bending experiments and series/parallel electrical connections, respectively.
Electricity Generation Performance
The developed moisture-driven electric generator demonstrated a maximum open-circuit voltage of 1.16 V and volumetric power density of 16.44 μW cm-³ at 65% relative humidity, outperforming many previously reported systems under similar environmental conditions.
The inclusion of hygroscopic salts and hydrophilic natural fibers promoted effective moisture uptake from the atmosphere, supporting ion dissociation and enhanced ionic conductivity within the composite matrix. The graphene-like conductive carbon coating further facilitated ion migration and charge collection at the electrodes.
Studies revealed that the electrical output depended strongly on internal moisture gradients; when the device lost moisture under dry conditions, voltage and current declined sharply but rapidly recovered upon re-exposure to ambient humidity. This reversible behavior indicates that the electricity originates from moisture-driven ionic transport rather than stored chemical energy, as the output diminished during equilibration of humidity gradients.
The asymmetric configuration of the current collectors generated directional ion drift, enabling stable charge separation and measurable potential differences. By varying electrode spacing and layering configurations, device performance was optimized, revealing trade-offs between internal resistance and ion transport distance.
The mechanical flexibility of the composite did not compromise electrical functionality, illustrating suitability for wearable and flexible electronic applications. Connecting multiple devices in series and parallel further increased voltage and current output, respectively, supporting scalable energy harvesting for practical use cases.
Importantly, the materials used were all derived from waste sources, including wild sugarcane stalks that naturally disperse post-monsoon and cigarette butts collected from public spaces, along with e-waste components for electrodes.
This renders the manufacturing process both cost-effective and environmentally sustainable by upcycling materials that would otherwise contribute to pollution.
Sustainable MEG Insights
This research successfully demonstrates a sustainable approach to harvesting electrical energy from ambient humidity by utilizing waste-derived natural fibers integrated with hygroscopic salts and recycled e-waste electrode materials.
The environmentally friendly fabrication process minimizes resource consumption by valorizing widely available waste materials, positioning this technology as a promising alternative for low-power energy harvesting in wearable and portable electronics.
Additionally, the proposed conceptual model advances understanding of moisture-material interactions in humidity-driven electricity generation. These findings support continued development and practical application of renewable, low-cost energy harvesters that harness atmospheric moisture without relying on chemical fuel or batteries, contributing to more sustainable energy solutions.
Journal Reference
Khan A.U.A., Nazmunnahar N., et al. (2026). Sustainable moisture-driven electricity generation using waste materials. Scientific Reports. DOI: 10.1038/s41598-026-61180-8, https://www.nature.com/articles/s41598-026-61180-8