| 1. |
- Alamia, Alberto, 1984, et al.
(author)
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Efficiency Comparison of Large-Scale Standalone, Centralized, and Distributed Thermochemical Biorefineries
- 2017
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In: Energy Technology. - : Wiley. - 2194-4296 .- 2194-4288. ; 5:8, s. 1435-1448
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Journal article (peer-reviewed)abstract
- © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.We present a comparison of three strategies for the introduction of new biorefineries: standalone and centralized drop-in, which are placed within a cluster of chemical industries, and distributed drop-in, which is connected to other plants by a pipeline. The aim was to quantify the efficiencies and the production ranges to support local transition to a circular economy based on biomass usage. The products considered are biomethane (standalone) and hydrogen/biomethane and sustainable town gas (centralized drop-in and distributed drop-in). The analysis is based on a flow-sheet simulation of different process designs at the 100MWbiomass scale and includes the following aspects: advanced drying systems, the coproduction of ethanol, and power-to-gas conversion by direct heating or water electrolysis. For the standalone plant, the chemical efficiency was in the range of 78-82.8% LHVa.r.50% (lower heating value of the as-received biomass with 50% wet basis moisture), with a maximum production of 72MWCH4 , and for the centralized drop-in and distributed drop-in plants, the chemical efficiency was in the range of 82.8-98.5% LHVa.r.50% with maximum production levels of 85.6MWSTG and 22.5MWH2 /51MWCH4 , respectively. It is concluded that standalone plants offer no substantial advantages over distributed drop-in or centralized drop-in plants unless methane is the desired product.
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| 2. |
- Andersson, Rassmus, et al.
(author)
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Micro versus Nano : Impact of Particle Size on the Flow Characteristics of Silicon Anode Slurries
- 2020
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In: ENERGY TECHNOLOGY. - : WILEY-V C H VERLAG GMBH. - 2194-4288 .- 2194-4296. ; 8:7
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Journal article (peer-reviewed)abstract
- Silicon is interesting for use as a negative electrode material in Li-ion batteries due to its extremely high gravimetric capacity compared with today's state-of-the-art material, graphite. However, during cycling the Si particles suffer from large volume changes, leading to particle cracking, electrolyte decompositions, and electrode disintegration. Although utilizing nm-sized particles can mitigate some of these issues, it would instead be more cost-effective to incorporate mu m-sized silicon particles in the anode. Herein, it is shown that the size of the Si particles not only influences the electrode cycling properties but also has a decisive impact on the processing characteristics during electrode preparation. In water-based slurries and suspensions containing mu m-Si and nm-Si particles, the smaller particles consistently give higher viscosities and more pronounced viscoelastic properties, particularly at low shear rates. This difference is observed even when the Si particles are present as a minor component in blends with graphite. It is found that the viscosity follows the particle volume fraction divided by the particle radius, suggesting that it is dependent on the surface area concentration of the Si particles.
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| 3. |
- Asfaw, Habtom Desta, Dr. 1986-, et al.
(author)
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Tailoring the Microstructure and Electrochemical Performance of 3D Microbattery Electrodes Based on Carbon Foams
- 2019
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In: Energy Technology. - : Wiley. - 2194-4288 .- 2194-4296.
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Journal article (peer-reviewed)abstract
- Three-dimensional (3D) carbon electrodes with suitable microstructural features and stable electrochemical performance are required for practical applications in 3D lithium (Li)-ion batteries. Herein, the optimization of the microstructures and electrochemical performances of carbon electrodes derived from emulsion-templated polymer foams are dealt with. Exploiting the rheological properties of the emulsion precursors, carbon foams with variable void sizes and specific surface areas are obtained. Carbon foams with an average void size of around 3.8 mu m are produced, and improvements are observed both in the coulombic efficiency and the cyclability of the carbon foam electrodes synthesized at 2200 degrees C. A stable areal capacity of up to 1.22 mAh cm(-2) (108 mAh g(-1)) is achieved at a current density of 50 mu A cm(-2). In addition, the areal capacity remains almost unaltered, i.e., 1.03 mAh cm(-2) (91 mAh g(-1)), although the cycling current density increases to 500 mu A cm(-2) indicating that the materials are promising for power demanding applications.
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| 4. |
- Aung, Soe Ko Ko, et al.
(author)
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Enhanced Thermal Stability of Low-Temperature Processed Carbon-Based Perovskite Solar Cells by a Combined Antisolvent/Polymer Deposition Method
- 2022
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In: Energy Technology. - : Wiley-VCH Verlagsgesellschaft. - 2194-4288 .- 2194-4296. ; 10:8
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Journal article (peer-reviewed)abstract
- Low-temperature processed carbon-based perovskite solar cells have received great attention due to low-cost, high stability, and simple preparation processes that can be employed in large-scale manufacturing. Carbon paste is deposited by techniques such as doctor blading or screen printing. However, solvents from this paste can damage the perovskite or underlying layers resulting in poor performance of solar cells. Furthermore, carbon is not an ideal hole-selective contact. To overcome these issues, the antisolvent treatment is combined with the deposition of a polymeric hole conductor. Specifically, poly(3-hexylthiophene) (P3HT), added into the chlorobenzene antisolvent, improves perovskite morphology and reduces interfacial carrier recombination. As a result, the power conversion efficiency (PCE) of solar cells with the device structure SnO2/MAPbI3/P3HT/carbon increases to 12.16% from 10.6% of pristine devices without P3HT, using pure antisolvent. For poly(triarylamine) hole conductor in the same method, PCE improves only slightly to 11.1%. After 260 h of thermal stress at 82 °C, the P3HT-additive devices improve PCE up to 13.2% in air and maintain 91% of their initial efficiency over 800 h.
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| 5. |
- Azad, Abdul-Majeed, 1957, et al.
(author)
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Examining the Cu-Mn-O Spinel System as an Oxygen Carrier in Chemical Looping Combustion
- 2013
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In: Energy Technology. - : Wiley. - 2194-4296 .- 2194-4288. ; 1:1, s. 59-69
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Journal article (peer-reviewed)abstract
- Chemical-looping combustion (CLC) and chemical-looping combustion with oxygen uncoupling (CLOU) are attractive alternatives to conventional combustion that provide efficient and direct separation of CO2. Both processes use metaloxides as oxygen carriers to transfer oxygen between two reactor vessels: the air and fuel reactors. Although monometallic oxides (such as Mn3O4, Fe2O3, NiO, and CuO) have been successfully employed as oxygen carriers, double oxides of the general formula CuxMn3_xO4 in the CuO–Mn2O3 system are examined in this work. The carrier was produced by mixing, extruding, and calcining a 1:1 molar (30.8:69.2 mass ratio) mixture of CuO and Mn2O3 at 950 8C for 6 or 12 h in static air. XRD analysis revealed that spinels of the general formula CuxMn3_xO4 were formed with 0.1_x_2.5 in which x=3Cu/(Cu+Mn). The chemical-looping performance was evaluated in a laboratory-scale fluidized-bed reactor from 800–850 8C over several alternating redox cycles using CH4 as the fuel. The oxygen carrier exhibited reproducible and stable reactivity behavior for both reducing and oxidizing periods in this temperature range. This characteristic makes the system an ideal oxygen-carrier material for CLOU. Moreover, the spinels in the CuxMn3_xO4 series are endowed with favorable physicochemical attributes (such as fast redox processes, high crushing strength, and demonstrated CLOU behavior) and may be viable alternatives to CuO–Cu2O and Mn2O3–Mn3O4 as potential CLOU materials.
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| 6. |
- Björklund, Erik, et al.
(author)
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Temperature dependence of electrochemical degradation in LiNi1/3Mn1/3Co1/3O2/Li4Ti5O12 cells
- 2019
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In: Energy Technology. - : Wiley. - 2194-4288 .- 2194-4296. ; 7:9
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Journal article (peer-reviewed)abstract
- Aging mechanisms in lithium‐ion batteries are dependent on the operational temperature, but the detailed mechanisms on what processes take place at what temperatures are still lacking. The electrochemical performance and capacity fading of the common cell chemistry LiNi1/3Mn1/3Co1/3O2 (NMC)/Li4Ti5O12 (LTO) pouch cells are studied at temperatures 10, 30, and 55 °C. The full cells are cycled with a moderate upper cutoff potential of 4.3 V versus Li+/Li. The electrode interfaces are characterized postmortem using photoelectron spectroscopy techniques (soft X‐ray photoelectron spectroscopy [SOXPES], hard X‐ray photoelectron spectroscopy [HAXPES], and X‐ray absorption near edge structure [XANES]). Stable cycling at 30 °C is explained by electrolyte reduction forming a stabilizing interphase, thereby preventing further degradation. This initial reaction, between LTO and the electrolyte, seems to be beneficial for the NMC–LTO full cell. At 55 °C, continuous electrolyte reduction and capacity fading are observed. It leads to the formation of a thicker surface layer of organic species on the LTO surface than at 30 °C, contributing to an increased voltage hysteresis. At 10 °C, large cell‐resistances are observed, caused by poor electrolyte conductivity in combination with a relatively thicker and LixPFy‐rich surface layer on LTO, which limit the capacity.
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| 7. |
- Etman, Ahmed, et al.
(author)
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On the Capacities of Freestanding Vanadium Pentoxide-Carbon Nanotube-Nanocellulose Paper Electrodes for Charge Storage Applications
- 2020
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In: ENERGY TECHNOLOGY. - : WILEY-V C H VERLAG GMBH. - 2194-4288 .- 2194-4296. ; 8:12
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Journal article (peer-reviewed)abstract
- Herein, a one-step protocol for synthesizing freestanding 20 mu m thick cellulose paper electrodes composed of V2O5 . H2O nanosheets (VOx), carbon nanotubes (CNTs), and Cladophora cellulose (CC) is reported. In 1.0 m Na2SO4, the VOx-CNT-CC electrodes deliver capacities of about 200 and 50 C g(-1) at scan rates of 20 and 500 mV s(-1), respectively. The obtained capacities are compared with the theoretical capacities and are discussed based on the electrochemical reactions and the mass loadings of the electrodes. It is shown that the capacities are diffusion rate limited and, consequently, depend on the distribution and thickness of the V2O5 . H2O nanosheets, whereas the long-term cycling stabilities depend on vanadium species dissolving in the electrolyte. The electrodes feature high mass loadings (2 mg cm(-2)), good rate performances (25% capacity retention at 500 mV s(-1)), and capacity retentions of 85% after 8000 cycles. A symmetric VOx-CNT-CC energy storage device with a potential window of about 1 V exhibits a capacity of 40 C g(-1) at a scan rate of 2 mV s(-1).
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| 8. |
- Etman, Ahmed S., et al.
(author)
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Acetonitrile-Based Electrolytes for Rechargeable Zinc Batteries
- 2020
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In: Energy technology. - : Wiley. - 2194-4288 .- 2194-4296. ; 8:9
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Journal article (peer-reviewed)abstract
- Herein, Zn plating-stripping onto metallic Zn using a couple of acetonitrile (AN)-based electrolytes (0.5 mZn(TFSI)(2)/AN and 0.5 mZn(CF3SO3)(2)/AN) is studied. Both electrolytes show a reversible Zn plating/stripping over 1000 cycles at different applied current densities varying from 1.25 to 10 mA cm(-2). The overpotentials of Zn plating-stripping over 500 cycles at constant current of 1.25 and 10 mA cm(-2)are +/- 0.05 and +/- 0.2 V, respectively. X-ray photoelectron spectroscopy analysis reveals that no decomposition product is formed on the Zn surface. The anodic stability of four different current collectors of aluminum foil (Al), carbon-coated aluminum foil (C/Al), TiN-coated titanium foil (TiN/Ti), and multiwalled carbon nanotube paper (MWCNT-paper) is tested in both electrolytes. As a general trend, the current collectors have a higher anodic stability in Zn(TFSI)(2)/AN compared with Zn(CF3SO3)(2)/AN. The Al foil displays the highest anodic stability of approximate to 2.25 V versus Zn2+/Zn in Zn(TFSI)(2)/AN electrolyte. The TiN/Ti shows a comparable anodic stability with that of Al foil, but its anodic current density is higher than Al. The promising reversibility of the Zn plating/stripping combined with the anodic stability of Al and TiN/Ti current collectors paves the way for establishing highly reversible Zn-ion batteries.
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| 9. |
- Fenske, Markus, et al.
(author)
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Improved Electrical Performance of Perovskite Photovoltaic Mini-Modules through Controlled PbI2 Formation Using Nanosecond Laser Pulses for P3 Patterning
- 2021
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In: Energy Technology. - : Wiley. - 2194-4288 .- 2194-4296. ; 9:4
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Journal article (peer-reviewed)abstract
- The upscaling of perovskite solar cells to modules requires the patterning of the layer stack in individual cells that are monolithically interconnected in series. This interconnection scheme is composed of three lines, P1–P3, which are scribed using a pulsed laser beam. The P3 scribe is intended to isolate the back contact layer of neighboring cells, but is often affected by undesired effects such as back contact delamination, flaking, and poor electrical isolation. Herein, the influence of the laser pulse duration on the electrical and compositional properties of P3 scribe lines is investigated. The results show that both nanosecond and picosecond laser pulses are suitable for P3 patterning, with the nanosecond pulses leading to a higher open circuit voltage, a higher fill factor, and a higher power conversion efficiency. It is found that the longer pulse duration resultes in a larger amount of PbI2 formed within the P3 line and a thin Br-rich interfacial layer which both effectively passivate defects at the scribe line edges and block charge carrier in its vicinity. Thus, nanosecond laser pulses are preferable for P3 patterning as they promote the formation of beneficial chemical phases, resulting in an improved photovoltaic performance.
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| 10. |
- Jeschull, Fabian, et al.
(author)
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Water-Soluble Binders for Lithium-Ion Battery Graphite Electrodes : Slurry Rheology, Coating Adhesion and Electrochemical Performance
- 2017
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In: Energy technology: generation, conversion, storage, distribution. - : Wiley. - 2194-4296. ; 5:11, s. 2108-2118
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Journal article (peer-reviewed)abstract
- Water-processable composite electrodes are attractive both ecologically and economically. The binders sodium carboxymethyl cellulose (CMC-Na) and poly(sodium acrylate) (PAA-Na) were shown to have improved electrochemical performance over conventional binders. In many studies, a binder content of approximately 10 wt % has been applied, which is not suitable for large-scale electrode production due to viscosity and energy-density considerations. Therefore, we examined herein three electrode formulations with binder contents of 4 wt %, namely, CMC-Na:SBR (SBR=styrene butadiene rubber), PAA-Na, and CMC-Na:PAA-Na, on both laboratory and pilot scales. The formulations were evaluated on the basis of slurry rheology, coating adhesion, and electrochemical behavior in half- and full-cells. CMC-Na:SBR composites provided the best coating adhesion, independent of the mass loading and scale, and also showed the best capacity retention after 100 cycles. Previously reported merits of better cycling efficiencies and solid–electrolyte interphase formation for graphite–PAA composites appeared to vanish upon reducing the binder content to realistic levels.
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