A recent study conducted by a team at University College London has uncovered an important correlation between form and function in supercapacitor materials. They ran an extensive study investigating the role of 3D structure in the properties of supercapacitors built by biocarbon-based materials, derived from plant cellulose. Their findings elucidate how high capacity, environmentally-friendly supercapacitors can be created, potentially out-performing conventional supercapacitors, leading the way to a greener future for energy usage.
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Improved energy systems and a greener future
The world is facing a rapidly depleting fossil fuel resource, as well as a growing population, and along with it, growing demand for technology and devices. In addition to this, there is a growing concern for climate change, resulting in an increased requirement for environmentally-friendly alternatives to energy sources. This is what encouraged the team at UCL, lead by Dina Ibrahim Abouelamaiem, to develop a method to provide improved energy systems and a greener future.
Supercapacitors will be able to offer wide applicability, high efficiency, and flexibility to energy storage and conversion systems, capable of being paired with renewable energy sources, reducing our carbon footprint and future-proof our energy supply.
Abouelamaiem’s team investigated how common precious metals and chemicals that are presently used to produce supercapacitors could be replaced by bio-carbon materials derived from plant cellulose, an environmentally-friendly alternative.
Exploring the nanostructure of supercapacitors
Supercapacitors are fundamental for the future of energy usage. They are built with the capabilities of the storage of high-power densities for a long time. They fill the space between batteries and fuel cells. The team at UCL worked to gain a deeper knowledge of how the nanostructure of supercapacitors could impact their function. The study used biocarbon electrodes which were activated with potassium hydroxide, providing a model system of an alternative supercapacitor. Using several techniques, including SEM (scanning electron microscopy), XPS (X-ray photoelectron spectroscopy), BET (Brunauer-Emmett-Teller theory for nitrogen adsorption), and X-ray CT (X-ray computed tomography), to gain an understanding of the relationship between structure and performance of supercapacitors. By using this combination of techniques, the researchers were able to analyze the nano-, micro-, meso- and macro-pores at the same time. The results showed that a hierarchical porous network was essential for electrode materials within the supercapacitors to function at their highest efficiency.
The future of supercapacitors
The study revealed that the electrochemical performance of supercapacitors does not rely solely on high surface areas. Their rigorous testing uncovered that optimum pore size distribution is also essential, specifically at low current densities. The researchers observed that performance improvement resulted from the formation of a hierarchical structure, from a mixture of pore sizes nestling within each other. They found a direct correlation between low cell resistance and high specific surface area, leading to a high specific capacitance.
The results suggest that interplaying morphological factors contribute to double-layer capacitance. Further to this, the findings support that the morphological factors are linked with performance rates over numerous length scales. Finally, the research has been able to expose a new potential pathway to explore for the optimization of supercapacitor materials, beginning with activated carbons.
What was achieved by the team at UCL will inform the development and future research into efficient and high performing energy storage devices, paving the way for a greener future through aiding the development of better energy storage options that can be used to support renewable technology.
Source
https://physicsworld.com/a/supercapacitor-nano-architecture-designing-a-plant-powered-future/
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