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1362. Characterization of electrochemical processes in metal-organic batteries by X-ray Raman spectroscopyAva Rajh, Iztok Arčon, Klemen Bučar, Matjaž Žitnik, Marko Petric, Alen Vižintin, Jan Bitenc, Urban Košir, Robert Dominko, Hlynur Gretarsson, Martin Sundermann, Matjaž Kavčič, 2022, original scientific article Abstract: X-ray Raman spectroscopy (XRS) is an emerging
spectroscopic technique that utilizes inelastic scattering of hard Xrays
to study X-ray absorption edges of low Z elements in bulk
material. It was used to identify and quantify the amount of
carbonyl bonds in a cathode sample, in order to track the redox
reaction inside metal−organic batteries during the charge/
discharge cycle. XRS was used to record the oxygen K-edge
absorption spectra of organic polymer cathodes from different
multivalent metal−organic batteries. The amount of carbonyl bond
in each sample was determined by modeling the oxygen K-edge
XRS spectra with the linear combination of two reference compounds that mimicked the fully charged and the fully discharged
phases of the battery. To interpret experimental XRS spectra, theoretical calculations of oxygen K-edge absorption spectra based on
density functional theory were performed. Overall, a good agreement between the amount of carbonyl bond present during different
stages of battery cycle, calculated from linear combination of standards, and the amount obtained from electrochemical
characterization based on measured capacity was achieved. The electrochemical mechanism in all studied batteries was confirmed to
be a reduction of double carbonyl bond and the intermediate anion was identified with the help of theoretical calculations. X-ray
Raman spectroscopy of the oxygen K-edge was shown to be a viable characterization technique for accurate tracking of the redox
reaction inside metal−organic batteries.
Keywords: X-ray Raman spectroscopy, meta-organic batteries, oxygen K-edge XANES, electrochemical processes
Published in RUNG: 24.03.2022; Views: 1753; Downloads: 20
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1363. Nutritional quality and safety of the spirulina dietary supplements sold on the Slovenian marketJasmina Masten, Marta Jagodic Hudobivnik, Marijan Nečemer, Katarina Vogel-Mikuš, Iztok Arčon, Nives Ogrinc, 2022, original scientific article Abstract: The microalgae Spirulina may be a popular dietary supplement rich in essential nutrients
and vitamins, but oversight of the supplement industry, in general, remains limited, and increasing
incidents of adulteration, misbranding, and undeclared ingredients together with misleading claims
create potential risks. In response, this study characterized the elemental, amino acid and fatty acid
content of commercially available Spirulina supplements in Slovenia using EDXRF, ICP-MS and
GC-MS and compared the results with their nutritional declaration. The gathered data confirm that
Spirulina supplements are a good source of calcium (0.15 to 29.5% of RDA), phosphorous (3.36–26.7%
of RDA), potassium (0.5 to 7.69% of RDA) and selenium (0.01 to 38.6% of RDA) when consumed
within recommended amounts. However, although iron contents were relatively high (7.64 to 316%
of RDA), the actual bioavailability of iron was much lower since it was mainly present as the ferric
cation. This study also confirms that pure Spirulina supplements are a good source of essential
and non-essential amino acids, and !-6 but not !-3 polyunsaturated fatty acids. The presence of
additives resulted in significant variation in nutrient content and, in some instances, lower product
quality. Moreover, a high proportion (86.7%) of inappropriate declarations regarding the elemental
content was observed. Overall, the study conclusions underline the need for a stricter control system
for Spirulina-based supplements.
Keywords: Spirulina, microalgae, cyanobacteria, elements, toxic elements, amino acids, fatty acids, authenticity, safety, quality
Published in RUNG: 24.03.2022; Views: 1600; Downloads: 0
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1368. Affinity-based isolation of extracellular vesicles by means of single-domain antibodies bound to macroporous methacrylate-based copolymerLidija Filipovic, Milica Spasojevic, Radivoje Prodanovic, Aleksandra Korac, Suzana Matijasevic, Goran Brajuskovic, Ario De Marco, Milica Popovic, 2022, original scientific article Keywords: nanobodies, immunopurification, extracellular vesicles, polymers
Published in RUNG: 18.03.2022; Views: 1651; Downloads: 0
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1369. Coevaporation of doped inorganic carrier-selective layers for high-performance inverted planar perovskite solar cellsJiexuan Jiang, Andraž Mavrič, Nadiia Pastukhova, Matjaž Valant, Qiugui Zeng, Zeyu Fan, Beibei Zhang, Yanbo Li, 2022, original scientific article Abstract: Inorganic carrier selective layers (CSLs), whose conductivity can be effectively tuned by doping, offer low-cost and stable alternatives for their organic counterparts in perovskite solar cells (PSCs). Herein, we employ a dual-source electron-beam co-evaporation method for the controlled deposition of copper-doped nickel oxide (Cu:NiO) and tungsten-doped niobium oxide (W:Nb2O5) as hole and electron transport layers, respectively. The mechanisms for the improved conductivity using dopants are investigated. Owing to the improved conductivity and optimized band alignment of the doped CSLs, the all-inorganic-CSLs-based PSCs achieves a maximum power conversion efficiency (PCE) of 20.47%. Furthermore, a thin titanium buffer layer is inserted between the W:Nb2O5 and the silver electrode to prevent the halide ingression and improve band alignment. This leads to a further improvement of PCE to 21.32% and a long-term stability (1200 h) after encapsulation. Finally, the large-scale applicability of the doped CSLs by co-evaporation is demonstrated for the device with 1 cm2 area showing a PCE of over 19%. Our results demonstrate the potential application of the co-evaporated CSLs with controlled doping in PSCs for commercialization.
Keywords: carrier selective layers, Cu-doped nickel oxide, electron-beam evaporation, perovskite solar cells, W-doped niobium oxide
Published in RUNG: 17.03.2022; Views: 1837; Downloads: 121
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