| 1. |
- Anikina, E. V., et al.
(författare)
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Influence of Kubas-type interaction of B–Ni codoped graphdiyne with hydrogen molecules on desorption temperature and storage efficiency
- 2020
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Ingår i: Materials Today Energy. - : Elsevier. - 2468-6069. ; 16
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated functionalized 2D carbon allotrope, graphdiyne (GDY), as a promising hydrogen storage media. Density functional theory with a range of vdW corrections was employed to study Ni decoration of pristine and boron-doped GDY and the interaction of resulting structures with molecular hydrogen. We showed that boron-doped GDY is thermally stable at 300 K, though, its synthesis requires an endothermic reaction. Also, boron doping enhances Ni binding with the graphdiyne by increasing the charge transfer from Ni to GDY. Ni doping drastically influenced hydrogen adsorption energies: they rise from ~70 meV per H2 molecule on pristine GDY to a maximum of 1.29 eV per H2 becoming too high in value for room temperature reversible applications. Boron doping improves the situations: in this case, after Ni decoration desorption temperature estimation is ~300–500 K. Overall, each Ni adatom on B-doped GDY can bind only one H2 molecule within the needed energy range, which gives low hydrogen uptake (~1.2 wt%). However, doping with boron led to the decrease in the value of hydrogen adsorption energy and good desorption temperature estimations, therefore, codoping of metal atoms and boron could be an effective strategy for other transition metals.
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| 2. |
- Asfaw, Habtom Desta, Dr. 1986-, et al.
(författare)
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Facile synthesis of hard carbon microspheres from polyphenols for sodium-ion batteries : insight into local structure and interfacial kinetics
- 2020
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Ingår i: Materials Today Energy. - : Elsevier BV. - 2468-6069. ; 18
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Tidskriftsartikel (refereegranskat)abstract
- Hard carbons are the most promising negative active materials for sodium ion storage. In this work, a simple synthesis approach is proposed to produce hard carbon microspheres (CMSs) (with a mean diameter of ~1.3 μm) from resorcinol-formaldehyde precursors produced via acid-catalyzed polycondensation reaction. Samples prepared at 1200, 1400, and 1500 oC showed different electrochemical behavior in terms of reversible capacity, initial coulombic efficiency (iCE), and the mechanism of sodium ion storage. The specific capacity contributions from the flat voltage profile (<0.1 V) and the sloping voltage region (0.1–1 V) showed strong correlation to the local structure (and carbonization temperature) determined by the interlayer spacing (d002) and the Raman ID/IG ratio of the hard carbons (HCs) and the rate of cycling. Electrochemical tests indicated that the HC synthesized at 1500 oC performed best with an iCE of 85–89% and a reversible capacity of 300–340 mAh g−1 at 10 mA g−1, with the majority of charge stored below 0.1 V. The d002 and the ID/IG ratio for the sample were ~3.7 Å and ~1.27, respectively, parameters indicative of the ideal local structure in HCs required for optimum performance in sodium-ion cells. In addition, galvanostatic tests on three-electrode half-cells cells revealed that sodium metal plating occurred as cycling rates were increased beyond 80 mA g−1 leading to considerably high capacity and poor coulombic efficiency, a point that must be considered in full-cell batteries. Pairing the hard CMS electrodes with Prussian white positive electrode, a proof-of-concept cell could provide a specific capacity of almost 100 mAh g−1 maintained for more than 50 cycles with a nominal voltage of 3 V.
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| 3. |
- Calcagno, Giulio, 1990, et al.
(författare)
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Fast charging negative electrodes based on anatase titanium dioxide beads for highly stable Li-ion capacitors
- 2020
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Ingår i: Materials Today Energy. - : Elsevier BV. - 2468-6069. ; 16
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Tidskriftsartikel (refereegranskat)abstract
- Hybrid energy storage systems aim to achieve both high power and energy densities by combining supercapacitor-type and battery-type electrodes in tandem. The challenge is to find sustainable materials as fast charging negative electrodes, which are characterized by high capacity retention. In this study, mesoporous anatase beads are synthetized with tailored morphology to exploit fast surface redox reactions. The TiO2-based electrodes are properly paired with a commercial activated carbon cathode to form a Li-ion capacitor. The titania electrode exhibits high capacity and rate performance. The device shows extremely stable performance with an energy density of 27 mWh g-1 at a specific current of 2.5 A g−1 for 10,000 cycles. The remarkable stability is associated with a gradual shift of the potential during cycling as result of the formation of cubic LiTiO2 on the surface of the beads. This phenomenon renews the interest in using TiO2 as negative electrode for Li-ion capacitors.
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| 4. |
- Camut, J., et al.
(författare)
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Aluminum as promising electrode for Mg-2(Si,Sn)-based thermoelectric devices
- 2021
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Ingår i: Materials Today Energy. - : Elsevier. - 2468-6069. ; 21
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Tidskriftsartikel (refereegranskat)abstract
- The solid solutions of magnesium silicide and magnesium stannide Mg-2(Si,Sn) are high-performance thermoelectric (TE) materials with the advantage of being composed of light, cheap, and abundant elements. Therefore, they are especially attractive for the conversion of remnant heat into electricity in fields like the automotive sector or the aerospace industry. The optimization of Mg-2(Si,Sn)-based thermoelectric generators requires establishing a suitable electrode to ensure unhindered conduction of the electrical current through the module. We have tested aluminum for such applications and developed a technological process for joining. The obtained functionalized TE legs showed electrical contact resistances below 10 mu Omega cm(2) for both p-and n-type materials and the values are preserved or even lowered with annealing. The p-type material is found to be stable and in the n-type, there is no indication for a charge carrier compensation due to the electrode, as was previously reported e.g. for Cu and Ag. Comparison with other reported electrodes shows that aluminum is so far the most suitable electrode for an Mg-2(Si,Sn)-based module.
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| 5. |
- Castin, N., et al.
(författare)
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The dominant mechanisms for the formation of solute-rich clusters in low-Cu steels under irradiation
- 2020
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Ingår i: Materials Today Energy. - : Elsevier BV. - 2468-6069. ; 17
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Tidskriftsartikel (refereegranskat)abstract
- The formation of nano-sized, coherent, solute-rich clusters (NSRC) is known to be an important factor causing the degradation of the macroscopic properties of steels under irradiation. The mechanisms driving their formation are still debated. This work focuses on low-Cu reactor pressure vessel (RPV) steels, where solute species are generally not expected to precipitate. We rationalize the processes that take place at the nanometer scale under irradiation, relying on the latest theoretical and experimental evidence on atomic-level diffusion and transport processes. These are compiled in a new model, based on the object kinetic Monte Carlo (OKMC) technique. We evaluate the relevance of the underlying physical assumptions by applying the model to a large variety of irradiation experiments. Our model predictions are compared with new experimental data obtained with atom probe tomography and small angle neutron scattering, complemented with information from the literature. The results of this study reveal that the role of immobilized self-interstitial atoms (SIA) loops dominates the nucleation process of NSRC.
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| 6. |
- Chen, C., et al.
(författare)
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Molecular engineering of ionic type perylenediimide dimer-based electron transport materials for efficient planar perovskite solar cells
- 2018
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Ingår i: Materials Today Energy. - : Elsevier Ltd. - 2468-6069. ; 9, s. 264-270
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Tidskriftsartikel (refereegranskat)abstract
- The main of this work is to overcome the drawbacks of the traditional fullerene derivatives used as electron transport materials (ETMs) for perovskite solar cells (PSCs). Herein, a new strategy to design non-fullerene ETMs is presented by molecular engineering to include charged moieties in the ETM. The designed ETM FA2+-PDI2 is intrinsically ionic and the incorporated counter ions in FA2+-PDI2 significantly increase the electron conductivity and improve the film formation properties. Through careful device optimization, PSCs based on the ionic ETM FA2+-PDI2 exhibit an impressive average power conversion efficiency (PCE) of 17.0%, which is comparable to the PSC based on PC61BM (17.5%). The superior photovoltaic performance can be attributed to efficient electron extraction and effective electron transfer in the PSCs. This work provides important insights regarding the future design of new and efficient non-fullerene ETMs for PSCs.
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| 7. |
- Eiler, Konrad, et al.
(författare)
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Oxygen reduction reaction and proton exchange membrane fuel cell performance of pulse electrodeposited Pt–Ni and Pt–Ni–Mo(O) nanoparticles
- 2022
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Ingår i: Materials Today Energy. - : Elsevier Ltd. - 2468-6069. ; 27
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Tidskriftsartikel (refereegranskat)abstract
- Proton exchange membrane fuel cells (PEMFCs) are an important alternative to fossil fuels and a complement to batteries for the electrification of vehicles. However, their high cost obstructs commercialization, and the catalyst material, including its synthesis, constitutes one of the major cost components. In this work, Pt–Ni and Pt–Ni–Mo(O) nanoparticles (NPs) of varying composition have been synthesized in a single step by pulse electrodeposition onto a PEMFC's gas diffusion layer. The proposed synthesis route combines NP synthesis and their fixation onto the microporous carbon layer in a single step. Both Pt–Ni and Pt–Ni–Mo(O) catalysts exhibit extremely high mass activities at oxygen reduction reaction (ORR) with very low Pt loadings of around 4 μg/cm2 due to the favorable distribution of NPs in contact with the proton exchange membrane. Particle sizes of 40–50 nm and 40–80 nm were obtained for Pt–Ni and Pt–Ni–Mo(O) systems, respectively. The highest ORR mass activities were found for Pt67Ni33 and Pt66Ni32–MoOx NPs. The feasibility of a single-step electrodeposition of Pt–Ni–Mo(O) NPs was successfully demonstrated; however, the ternary NPs are of more amorphous nature in contrast to the crystalline, binary Pt–Ni particles, due to the oxidized state of Mo. Nevertheless, despite their heterogeneous nature, the ternary NPs show homogeneous behavior even on a microscopic scale. © 2022 The Author(s)
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| 8. |
- Etman, Ahmed S., 1986-, et al.
(författare)
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Mo1.33CTz-Ti3C2Tz mixed MXene freestanding films for zinc-ion hybrid supercapacitors
- 2021
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Ingår i: Materials Today Energy. - : Elsevier. - 2468-6069. ; 22
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Tidskriftsartikel (refereegranskat)abstract
- The high demand on fast rechargeable batteries and supercapacitors combined with the limited resources of their active materials (e.g. Li and Co) motivate the exploration of sustainable energy storage systems such as Zn-ion hybrid supercapacitors. MXenes are two-dimensional materials with outstanding properties such as high conductivity and capacitance which enhance their performance in energy storage devices. Herein, we report on the use of freestanding Mo1.33CTz–Ti3C2Tz mixed MXene films in Zn-ion hybrid supercapacitors. The mixed MXene films are prepared from pristine MXene suspensions using a one-step vacuum filtration approach. The mixed MXene delivers capacities of about 159 and 59 mAh/g at scan rates of 0.5 and 100 mV/s, respectively. These capacity values are higher than the pristine MXene films and previously reported values for MXene electrodes in Zn-ion supercapacitors. Furthermore, the electrodes offer a promising capacity retention of about 90% after 8,000 cycles. In addition, the mixed MXene features energy densities of about 103 and 38 Wh/kg at power densities of 0.143 and 10.6 kW/kg, respectively. Insights into the effect of electrode thickness on rate performance and the mechanism of charge storage are also discussed. This study opens a venue for the use of Mo1.33CTz–Ti3C2Tz mixed MXene electrodes in sustainable energy storage systems with high energy density and power density.
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| 9. |
- Grieco, Rebecca, et al.
(författare)
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A significantly improved polymer||Ni(OH) 2 alkaline rechargeable battery using anthraquinone-based conjugated microporous polymer anode
- 2022
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Ingår i: Materials Today Energy. - : Elsevier BV. - 2468-6069. ; 27
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Tidskriftsartikel (refereegranskat)abstract
- Alkaline rechargeable batteries (ARBs) are predicted to be an attractive solution for large-scale electrochemical energy storage applications. However, their advancement is greatly hindered by the lack of high-performance and sustainable anode that can stably operate in less-corroding, low electrolyte concentration. Herein, we report the first example of polymer ARB able to operate in low concentrate electrolyte (1м potassium hydroxide [KOH]) due to the employment of a robust anthraquinone-based conjugated microporous polymer (IEP-11) as anode. The assembled IEP-11||Ni(OH)2 achieves high cell voltage (0.98 V), high gravimetric/areal capacities (150 mAh/g/7.2 mAh/cm2 at 3.5 and 65 mg/cm2, respectively), long cycle life (22,730 cycles, 960 h, 75% capacity retention at 20C), excellent rate performance (75 mAh/g at 50C) and low temperature operativity (75 mAh/g at −10 °C). Furthermore, rate capability, low-temperature performance and ability to prepare high mass loading anodes, along with low self-discharge is improved compared to conventional linear poly (anthraquinone sulfide) (PAQS) in commonly used 10 м KOH. This overall performance for IEP-11||Ni(OH)2 is not only far superior to that of PAQS||Ni(OH)2 owing to porous polymer's high specific surface area, combined micro-/mesoporosity and robust and mechanically stable three-dimensional (3D) architecture compared to the linear PAQS, but also surpass most of the reported organic||nickel [Ni]/cobalt [Co]/manganese [Mn] alkaline rechargeable batteries (ARBs).
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| 10. |
- Hernández, Guiomar, et al.
(författare)
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Polyimide-polyether bindersediminishing the carbon content in lithium-sulfur batteries
- 2017
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Ingår i: Materials Today Energy. - : Elsevier BV. - 2468-6069. ; 6, s. 264-270
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Tidskriftsartikel (refereegranskat)abstract
- Lithium-sulfur batteries are on the run to become the next generation energy storage technology. First of all due to its high theoretical energy density but also for its sustainability and low cost. However, there are still several challenges to take into account such as reducing the shuttle effect, decreasing the amount of conductive carbon to increase the energy density or enhancing the sulfur utilization. Herein, redox-active binders based on polyimide-polyether copolymers have been proposed as a solution to those drawbacks. These multiblock copolymers combine the ability of poly (ethylene oxide) to act as polysulfide trap and the properties of the imide groups to redox mediate the charge-discharge of sulfur. Thus, poly (ethylene oxide) block helps with the shuttle effect and mass transport in the electrode whereas the polyimide part enhances the charge transfer promoting the sulfur utilization. Sulfur cathodes containing pyromellitic, naphthalene or perylene polyimide-polyether binders featured improved cell performance in comparison with pure PEO binder. Among them, the electrode with naphthalene polyimide-PEO binder showed the best results with an initial capacity of 1300 mA h g(-1) at C/5, low polarization and 70% capacity retention after 30 cycles. Reducing the amount of carbon black in the cathode to 5 wt%, the cell with the redox-active binder was able to deliver 500 mA h g(-1) at C/5 with 78% capacity retention after 20 cycles. Our results demonstrate the possibility to reduce the amount of carbon by introducing polyimide-polyether copolymers as redox-active binders, increasing the sulfur utilization, redox kinetics and stability of the cell. (C) 2017 Elsevier Ltd. All rights reserved.
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