A recent article in Battery Energy outlines a method for converting cigarette filter waste (CFW) into carbon nanomaterials (CNMs) through a single-step, low-impact pyrolysis process. The goal is to repurpose this common waste material into electrodes for supercapacitors—devices that store energy and charge or discharge quickly, making them useful for clean energy systems.
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Background
With global waste levels rising, cigarette filters have become a persistent pollutant. They’re mainly made from cellulose acetate, a synthetic polymer that breaks down slowly and contributes microplastics and toxic substances to the environment. While usually discarded as non-recyclable waste, cigarette filters contain a high carbon content, making them a potential source of useful material.
Turning biomass and plastic waste into carbon-based nanomaterials has gained interest in recent years, as these materials offer high surface area, good conductivity, and strong electrochemical stability—key qualities for energy storage.
Cigarette filters, despite being widely available, have been largely overlooked in this space. Some also contain titanium dioxide (TiO2), which can improve the performance of resulting materials by enhancing their catalytic properties. Repurposing filters into nanomaterials offers a way to manage waste while contributing to clean energy technologies.
The Current Study
Researchers developed a simple process to convert used cigarette filters into CNMs. Filters from various brands were collected, cleaned to remove tobacco residue, and then subjected to pyrolysis at 800 °C in a nitrogen atmosphere. The temperature was increased at a steady rate of 10 °C per minute. This broke down the polymer structure and produced a carbon-rich material.
After pyrolysis, the material was treated with hydrochloric acid to remove metal impurities, rinsed with deionized water until reaching neutral pH, and sonicated for consistency. It was then vacuum-dried at 60 °C. The final product contained TiO2 and was suitable for use as an electrode without further modification.
To make supercapacitors, researchers coated these CNMs onto current collectors and tested different aqueous electrolytes, such as sulfuric acid and potassium hydroxide, to optimize performance.
Results and Discussion
The CNMs produced in this study showed structural and chemical features that are well-suited for supercapacitor use. Raman spectroscopy and X-ray diffraction confirmed a graphitic carbon structure with embedded TiO2.
The Raman spectra revealed a strong 2D band, pointing to few-layered, graphene-like structures, while XRD data showed peaks for both graphitic carbon and anatase-phase TiO2. This level of graphitization supports good electrical conductivity, and the TiO2 doping adds electrochemical functionality.
X-ray photoelectron spectroscopy showed that the CNMs were mainly composed of carbon, oxygen, nitrogen, and small amounts of titanium, with surface groups typical of carbon-based materials. Electrochemical tests showed strong performance: high specific capacitance, low internal resistance, and good cycling stability. The surface area reached around 590 m²/g, much higher than typical carbon materials, which contributes to better charge storage.
The material also showed clear pseudocapacitive behavior, driven by surface oxygen groups and the TiO2 content. These CNMs outperformed several previously studied biomass-derived materials, supporting their potential as a sustainable option for high-performance supercapacitor electrodes.
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Conclusion
This study shows that cigarette filter waste can be converted into useful carbon nanomaterials for supercapacitor electrodes through a simple, catalyst-free pyrolysis method. The resulting materials offer good surface area, chemical properties, and structural features that meet the needs of high-performance energy storage devices.
Beyond developing a new material, the work highlights a practical use for a major pollutant. By turning waste into energy components, the process supports both waste reduction and clean energy goals. The approach could be refined further for large-scale production and offers a path toward more sustainable energy storage technologies.
Journal Reference
Sivanandan A., et al. (2025). From Waste to Watts: Cigarette Filter Waste to Carbon Nanomaterial‐Based Supercapacitors for Sustainable Energy Storage Applications. Battery Energy. DOI: 10.1002/bte2.20240104, https://onlinelibrary.wiley.com/doi/full/10.1002/bte2.20240104