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- Malhotra, Jaskaran Singh, et al.
(author)
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From wood to supercapacitor electrode material via fast pyrolysis
- 2023
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In: Journal of Energy Storage. - : Elsevier Ltd. - 2352-152X .- 2352-1538. ; 57
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Journal article (peer-reviewed)abstract
- Adding high-value products, such as carbon-based electrode materials for electrochemical energy storage, to the value chain of biorefinery may increase the profits of the whole concept. In this work, carbon-based supercapacitor electrode materials were produced by chemical activation (using KOH) of two fractions of bio-oil (aerosol and condensed) as well as bio-char precursors, all of them originally made from fast pyrolysis of stem wood from pine and spruce. The produced materials show a hierarchical porous structure, a high surface area (1300–1500 m2 g−1) and, almost double the specific capacitance (149–152 F g−1 @ 50 mA g−1) compared to commercially available activated carbon (79 F g−1 @ 50 mA g−1). The benefit of using bio-oils compared to biochar is having an electrode material almost free from metal impurities alongside marginally higher energy storage performance. Together with the material yield in the production chain (fast pyrolysis and activation), a normalized energy storage value was presented for each material that may be used in the future to select the best techno-economic route for the whole concept. © 2022 The Authors
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| 2. |
- Sepman, Alexey, et al.
(author)
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Iron as recyclable electrofuel : Effect on particle morphology from multiple combustion-regeneration cycles
- 2024
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In: Combustion and Flame. - : Elsevier Inc.. - 0010-2180 .- 1556-2921. ; 259
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Journal article (peer-reviewed)abstract
- This work describes the morphological and material changes in the iron powder during four regeneration-combustion cycles. The regeneration in H2 and combustion in air experiments were made in a fluidized bed (FB) and an entrained flow reactor (EFR), respectively. The average size of the iron oxide particles more than doubled between the first and fourth combustion cycles, and many of the particles were hollow. The regeneration step did not change the size of the particles but increased their porosity. A mechanism is proposed that describes the formation of large-diameter hollow particles which increases as a function of the regeneration-combustion cycles. The observed increase in particle size and the change in particle morphology complicates the iron fuel concept, as it leads to a degradation of the structural stability of the particle with time.
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| 3. |
- Udayakumar, Mahitha, et al.
(author)
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Hierarchical porous carbon foam electrodes fabricated from waste polyurethane elastomer template for electric double-layer capacitors
- 2022
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In: Scientific Reports. - : Springer Nature. - 2045-2322. ; 12
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Journal article (peer-reviewed)abstract
- Plastic waste has become a major global environmental concern. The utilization of solid waste-derived porous carbon for energy storage has received widespread attention in recent times. Herein, we report the comparison of electrochemical performance of porous carbon foams (CFs) produced from waste polyurethane (PU) elastomer templates via two different activation pathways. Electric double-layer capacitors (EDLCs) fabricated from the carbon foam exhibited a gravimetric capacitance of 74.4 F/g at 0.1 A/g. High packing density due to the presence of carbon spheres in the hierarchical structure offered excellent volumetric capacitance of 134.7 F/cm3 at 0.1 A/g. Besides, the CF-based EDLCs exhibited Coulombic efficiency close to 100% and showed stable cyclic performance for 5000 charge–discharge cycles with good capacitance retention of 97.7% at 3 A/g. Low equivalent series resistance (1.05 Ω) and charge transfer resistance (0.23 Ω) due to the extensive presence of hydroxyl functional groups contributed to attaining high power (48.89 kW/kg). Based on the preferred properties such as high specific surface area, hierarchical pore structure, surface functionalities, low metallic impurities, high conductivity and desirable capacitive behaviour, the CF prepared from waste PU elastomers have shown potential to be adopted as electrodes in EDLCs.
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