| 1. |
- 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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| 2. |
- 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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| 3. |
- Hrachowina, Lukas, et al.
(författare)
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Realization of axially defined GaInP/InP/InAsP triple-junction photovoltaic nanowires for high-performance solar cells
- 2022
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Ingår i: Materials Today Energy. - : Elsevier BV. - 2468-6069. ; 27
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Tidskriftsartikel (refereegranskat)abstract
- III-V semiconductor-based planar multi-junction solar cells synthesized to match the solar spectrum, increase absorption, and reduce thermalization loss are today's world-record efficiency solar cells. Realizing similarly performing multi-junction III-V nanowire (NW) solar cells would require significantly less material and is more sustainable at lower cost than planar solar cells. The NW geometry allows expanding the range of compatible material combinations along the NW axis far beyond current multi-junction solar cells and enables promising applications in, for example, space power technology and smart windows. However, multi-junction NW photovoltaics have been hampered by the inability to electrically connect different materials in an axial geometry. We report the design and proof-of-principle demonstration of axially defined GaInP/InP/InAsP triple-junction photovoltaic NWs optimized for light absorption exhibiting an open-circuit voltage of up to 2.37 V. The open-circuit voltage is twice as large as previously reported for tandem-junction photovoltaic NWs and amounts to 94% of the sum of the respective single-junction NWs. Our findings pave the way for realizing the next generation of scalable, high-performance, and ultra-high power-to-weight ratio multi-junction, NW-based solar cells.
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| 4. |
- Mishra, Pushkar, et al.
(författare)
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Bifunctional catalytic activity of 2D boron monochalcogenides BX (X = S, Se, Te)
- 2022
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Ingår i: Materials Today Energy. - : Elsevier. - 2468-6069. ; 27
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Tidskriftsartikel (refereegranskat)abstract
- Photocatalysis and electrocatalysis are two sustainable and renewable technologies that can meet global energy demands in environmentally friendly ways. According to recent research, 2D boron monochalcogenides in the 1 T and 2 H phases are stable, strong, and broad bandgap semiconductors. Our calculations show a strong UV absorption ability and suitable band edge positions for water splitting oxidation and reduction, making it a good choice for an efficient photocatalyst. The development of bifunctional electrocatalysts has piqued the interest of researchers working in the field of electrocatalysts for fuel cells. The electrocatalytic properties of 2D boron monochalcogenides are also investigated for catalyzing both oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). The calculated overpotentials for OER/ORR mechanism are found to be 0.92/1.09 for BS (1 T), 1.00/0.59 for BS (2 H), 0.96/1.05 for BSe (1 T), 0.92/0.85 for BSe (2 H), and 1.10/0.92 for BTe (1 T), which are close to benchmark catalysts. The ORR overpotential of BS (2H) is 0.59 V, near well-known catalyst Pt (0.45 V). Therefore, our investigations indicate that the family of 2D materials, boron monochalcogenides, are promising photocatalyst and electrocatalyst candidates for OER and ORR.
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| 5. |
- Xiong, Shizhao, 1985, et al.
(författare)
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Lithium electrodeposition for energy storage: filling the gap between theory and experiment
- 2022
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Ingår i: Materials Today Energy. - : Elsevier BV. - 2468-6069. ; 28
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Lithium (Li) metal has been considered a promising anode material for high-energy-density rechargeable batteries, but its utilization is impeded by the nonuniform electrodeposition during the charging process which leads to poor cycling life and safety concerns. Thus, understanding the electrodeposition mechanism of Li-metal anode is of great importance to develop practical engineering strategies for rechargeable Li-metal batteries. The electrodeposition of Li is controlled by both thermodynamic and kinetic factors, such as the solvation free energy of Li-ions, the Li nucleation, the surface diffusion of Li atom, and the strength of the interaction between Li-ion and the electrolyte anion. The scale of the whole process from the Li-ion reduction to the growth of a Li nucleus goes from sub-nanometer up to a few micrometers, which poses an outstanding challenge to both experiments and simulation. In this perspective, we discuss the top-down, the bottom-up, and the middle-way approaches to this challenge and the possible synergies between them.
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