Matylda N. Guzik

• Baszczeńska, Oliwia; Niesporek, Kamil & Guzik, Matylda N. (2026). Powering the future: A comparative review of climate commitments, energy transition strategies, and hydrogen economy approaches in Poland and Norway. Energy Reports. 15. doi: 10.1016/j.egyr.2025.108975. Fulltekst i vitenarkiv Vis sammendrag

  This review compares Poland and Norway's efforts in implementation of strategies for energy transition and hydrogen economy development in view of the countries’ current and future climate commitments. The analysis highlights key differences, providing insight into the current conditions and challenges shaping future landscapes of energy and hydrogen in each country. Norway and Poland differ in the energy generation solutions; the former relies heavily on renewables, i.e., hydropower and wind, while the latter, still reliant on coal, faces challenges in increasing renewable energy share and modernizing the national power grid. At the same time, Poland's climate and energy policies are primarily defined by the EU membership and initiatives like the European Green Deal, while Norway as a non-EU country has a greater flexibility in developing and adopting its energy plans. Despite these differences, both countries are progressing in planning and implementing hydrogen initiatives, offering valuable lessons for other nations facing similar energy challenges.

• Sednev-Lugovets, Anton; Lu, Yang; Vistad, Ørnulv Bjørnsson; Carvalho, Patricia Almeida; Missyul, Alexander & Austrheim, Håkon Olaf [Vis alle 8 forfattere av denne artikkelen] (2025). The crystal structure of dypingite: understanding the long-range disorder. Journal of Applied Crystallography. ISSN 0021-8898. 58(6), s. 1908–1919. doi: 10.1107/S1600576725007915. Fulltekst i vitenarkiv Vis sammendrag

  Dypingite, a hydrated magnesium carbonate hydroxide mineral [Mg5(CO3)4(OH)2·XH2O, X = 5–6], exhibits promising catalytic and purification properties. Although it was discovered 55 years ago, the crystal structure of this compound has remained unknown due to its aggregated morphology and structural disorder. This work investigates the origin of this phenomenon through a systematic analysis of synthetic and natural mineral samples, using synchrotron powder X-ray diffraction, thermogravimetric analysis and transmission electron microscopy. The findings reveal that ambient humidity significantly influences dypingite's structural properties at room temperature. High humidity (80% relative humidity at 22 °C) causes inhomogeneous expansion of the unit cell along the crystallographic c axis, leading to long-range structural disorder. Conversely, at 20% relative humidity at 22 °C, the mineral structure exhibits a shorter c lattice constant and reduced structural disorder. Chemical analysis reveals that samples kept at 80% and 20% relative humidity for 10 days differ by one molecule of water of hydration, yielding Mg5(CO3)4.5(2)(OH)0.96(3)·6.0(2)H2O and Mg5(CO3)4.5(2)(OH)1.02(4)·5.0(2)H2O, respectively. The results obtained demonstrate that the crystal structure of dehydrated dypingite [Mg5(CO3)4.5(2)(OH)1.02(4)·5.0(2)H2O] derives from hydro­magnesite's unit cell tripled along the a axis. The analysis of the mineral crystal structure provides insight into the role of humidity on the structural properties of dypingite, including unit-cell dimensions and long-range disorder.

• Lu, Yang; Sednev-Lugovets, Anton; Carvalho, Patricia Almeida; Guzik, Matylda N.; Dayaghi, Amir Masoud & Dunkel, Kristina G [Vis alle 9 forfattere av denne artikkelen] (2025). Dypingite as a hydration series with reversible change of H2O content. American Mineralogist. ISSN 0003-004X. 111(5), s. 746–757. doi: 10.2138/am-2024-9603. Fulltekst i vitenarkiv Vis sammendrag

  Dypingite has recently been found to have promising applications in material and environmental sciences. However, its exploitation is limited due to its ambiguous identification via powder X-ray diffraction (PXRD), which is caused by the occurrence of several phases with similar structures and PXRD patterns to that of dypingite. Multiple dypingite-like phases with partially overlapping X-ray diffraction traces appear to exist. To better understand dypingite, we studied samples from Dypingdal and Feragen Ultramafic Body, Norway. Dypingite sensu stricto (s.s.), several dypingite-like phases, and hydromagnesite were identified by PXRD. Three regions of 2θ (CuKα) were recognized where diffraction peaks are readily observed to transition between dypingite s.s., dypingite-like phases, and hydromagnesite. The position of the peak at around 8.5° 2θ varies with the H2O contents measured by the thermogravimetric and Fourier transform infrared analyses, suggesting that structural and compositional characteristics of dypingite-like phases form a continuum between dypingite s.s. and hydromagnesite. Humidity incubation experiments at room temperature indicated a reversible change of H2O content between dypingite s.s. and dypingite-like phases. High humidity conditions increased H2O contents of dypingite-like phases to dypingite s.s., whereas low humidity conditions reversed the direction towards hydromagnesite, but without complete reaction. Such transition behavior suggests that the structures of dypingite s.s. and the dypingite-like phases are very similar, probably identical in building unit topology but with different degrees of hydration, whereas the structure of hydromagnesite is less closely related. This study draws attention to the sample processing on dypingite hydration series, contributes to the applications of this series in CO2 sequestration, and gives suggestions to the refinement of structures of dypingite and dypingite-like phases.

• Wyzga, Pawel; Macyk, Joanna; Lin, Yuan-Chih; Jensen, Emil Høj; Guzik, Matylda & Bienkowski, Krzysztof [Vis alle 8 forfattere av denne artikkelen] (2024). 3D-Printed Reactor for Coupling Photoelectrochemical (Sea)Water Splitting with Solid-State H<inf>2</inf> Storage. Catalysts. 14(12). doi: 10.3390/catal14120941. Fulltekst i vitenarkiv Vis sammendrag

  The modular photoelectrochemical (PEC) reactor accommodating eight photoelectrodes with a total active area of up to 46 cm2 has been designed and manufactured using the fused deposition modeling method. The device was equipped with an electrolyte flow system, a relay module for the photoelectrode connection, and a feedback-loop module for switching between counter electrodes. The performance and durability of the system were tested within three case study experiments. The water splitting process was successfully combined with an in situ hydrogen storage in the form of metal hydride phases (confirmed by powder X-ray diffraction) using Fe2O3- or WO3-based photoanodes and LaNi5-based cathodes. The PEC water oxidation at the anodes was realized either in a strongly alkaline electrolyte (pH > 13.5) or in acidified synthetic seawater (pH < 2) for Fe2O3 and WO3 electrodes, respectively. In the latter case, the photoresponse of the anodes decreased the cell charging voltage by 1.7 V at the current density of 60 mA∙g−1. When the seawater was used as an anolyte, the oxygen evolution reaction was accompanied by the chlorine evolution reaction. The manufactured PEC-metal hydride reactor revealed mechanical and chemical stability during a prolonged operation over 300 h and in the broad range of pH values.

• Lin, Yuan-Chih; Wyzga, Pawel; Macyk, Joanna; Macyk, Wojciech & Guzik, Matylda N. (2024). Solar-driven (photo)electrochemical devices for green hydrogen production and storage: Working principles and design. Journal of Energy Storage. ISSN 2352-152X. 82. doi: 10.1016/j.est.2024.110484. Fulltekst i vitenarkiv
• Jensen, Emil Høj; Lombardo, Loris; Girella, Alessandro; Guzik, Matylda N.; Züttel, Andreas & Milanese, Chiara [Vis alle 9 forfattere av denne artikkelen] (2023). The Effect of Y Content on Structural and Sorption Properties of A<inf>2</inf>B<inf>7</inf>-Type Phase in the La–Y–Ni–Al–Mn System. Molecules. ISSN 1431-5157. 28(9). doi: 10.3390/molecules28093749. Fulltekst i vitenarkiv Vis sammendrag

  Metal hydrides are an interesting group of chemical compounds, able to store hydrogen in a reversible, compact and safe manner. Among them, A2B7-type intermetallic alloys based on La-Mg-Ni have attracted particular attention due to their high electrochemical hydrogen storage capacity (∼400 mAh/g) and extended cycle life. However, the presence of Mg makes their synthesis via conventional metallurgical routes challenging. Replacing Mg with Y is a viable approach. Herein, we present a systematic study for a series of compounds with a nominal composition of La2-xYxNi6.50Mn0.33Al0.17, x = 0.33, 0.67, 1.00, 1.33, 1.67, focusing on the relationship between the material structural properties and hydrogen sorption performances. The results show that while the hydrogen-induced phase amorphization occurs in the Y-poor samples (x < 1.00) already during the first hydrogen absorption, a higher Y content helps to maintain the material crystallinity during the hydrogenation cycles and increases its H-storage capacity (1.37 wt.% for x = 1.00 vs. 1.60 wt.% for x = 1.67 at 50 °C). Thermal conductivity experiments on the studied compositions indicate the importance of thermal transfer between powder individual particles and/or a measuring instrument.

• Strandbakke, Ragnar; Wragg, David Stephen; Sørby, Magnus Helgerud; Guzik, Matylda; Gunnæs, Anette Eleonora & Szpunar, Iga [Vis alle 12 forfattere av denne artikkelen] (2022). Structural properties of mixed conductor Ba1−xGd1−yLax+yCo2O6−δ. Dalton Transactions. ISSN 1477-9226. 51(48), s. 18667–18677. doi: 10.1039/d2dt02277j. Fulltekst i vitenarkiv Vis sammendrag

  Ba1−xGd1−yLax+yCo2O6−δ (BGLC) compositions with large compositional ranges of Ba, Gd, and La have been characterised with respect to phase compositions, structure, and thermal and chemical expansion. The results show a system with large compositional flexibility, enabling tuning of functional properties and thermal and chemical expansion. We show anisotropic chemical expansion and detailed refinements of emerging phases as La is substituted for Ba and Gd. The dominating phase is the double perovskite structure Pmmm, which is A-site ordered along the c-axes and with O vacancy ordering along the b-axis in the Ln-layer. Phases emerging when substituting La for Ba are orthorhombic Ba-deficient Pbnm and cubic LaCoO3-based R[3 with combining macron]c. When La is almost completely substituted for Gd, the material can be stabilised in Pmmm, or cubic Pm[3 with combining macron]m, depending on thermal and atmospheric history. We list thermal expansion coefficients for x = 0–0.3, y = 0.2.

• Zhu, Junjie; Gudmundsdottir, Jonina Björg; Strandbakke, Ragnar; Both, Kevin Gregor; Aarholt, Thomas & Carvalho, Patricia Almeida [Vis alle 12 forfattere av denne artikkelen] (2021). Double Perovskite Cobaltites Integrated in a Monolithic and Noble Metal-Free Photoelectrochemical Device for Efficient Water Splitting. ACS Applied Materials & Interfaces. ISSN 1944-8244. 13(17), s. 20313–20325. doi: 10.1021/acsami.1c01900. Fulltekst i vitenarkiv Vis sammendrag

  Water photoelectrolysis has the potential to produce renewable hydrogen fuel, therefore addressing the intermittent nature of sunlight. Herein, a monolithic, photovoltaic (PV)-assisted water electrolysis device of minimal engineering and of low (in the μg range) noble-metal-free catalysts loading is presented for unassisted water splitting in alkaline media. An efficient double perovskite cobaltite catalyst, originally developed for high-temperature proton-conducting ceramic electrolyzers, possesses high activity for the oxygen evolution reaction in alkaline media at room temperatures too. Ba1–xGd1–yLax+yCo2O6−δ (BGLC) is combined with a NiMo cathode, and a solar-to-hydrogen efficiency of 6.6% in 1.0 M NaOH, under 1 sun simulated illumination for 71 h, is demonstrated. This work highlights how readily available earth-abundant materials and established PV methods can achieve high performance and stable and monolithic photoelectrolysis devices with potential for full-scale applications.

• Wijayanti, Ika Dewi; Mølmen, Live; Denys, Roman Volodymyrovich; Guzik, Matylda Natalia; Gorsse, Stéphane & Bobet, Jean-Louis [Vis alle 7 forfattere av denne artikkelen] (2021). Studies of the effect of melt spinning on the electrochemical properties of the AB2 Laves phase alloys. Journal of Mechanical Engineering and Sciences (JMES). ISSN 2289-4659. 5(1), s. 24–29. doi: 10.12962/j25807471.v5i1.8466. Fulltekst i vitenarkiv Vis sammendrag

  A comparative study of the effect of melt spinning on the electrochemical properties of the C14 and C15 AB2 alloys has been performed. The wheel speeds of 630, 2100, and 4100 cm/s were applied during the rapid solidification of both alloys. The structural analysis of the formed phases was performed by X-ray powder diffraction (XRD), while their microstructural morphology was studied by scanning electron microscopy (SEM). In both alloys a tremendous grain refinement due to the melt spinning process was observed: In addition, melt spinning also significantly contributed to the morphological variation of the microstructural changes in C14 alloys which showed changes from the equiaxed grain at lower speed to the small dendrites at higher speed. In contrast to the C14 alloys, the morphological variation was not observed for the C15 alloys. Furthermore, for both C14 and C15 alloys melt-spun at 2100 cm/s the maximum capacities of 435 and 414 mAh/g were achieved, respectively. As both alloys revealed the significant grain refinement due to the melt spinning, an increase in electrochemical capacity was achieved. However, the melt spinning parameters need to be further optimized to improve poor activation behavior of the rapidly solidified alloys.

• Wijayanti, Ika Dewi; Denys, Roman Volodymyrovich; Suwarno, Suwarno; Volodin, Alexei A.; Lototskyy, Mykhaylo V. & Guzik, Matylda N. [Vis alle 10 forfattere av denne artikkelen] (2020). Hydrides of Laves type Ti–Zr alloys with enhanced H storage capacity as advanced metal hydride battery anodes. Journal of Alloys and Compounds. ISSN 0925-8388. 828. doi: 10.1016/j.jallcom.2020.154354. Fulltekst i vitenarkiv Vis sammendrag

  The present work was focused on the studies of the effect of variation of stoichiometric composition of Ti–Zr based AB2±x Laves phase alloys by changing the ratio between A (Ti + Zr) and B (Mn + V + Fe + Ni) components belonging to both hypo-stoichiometric (AB1.90, AB1.95) and over-stoichiometric (AB2.08) alloys further to the stoichiometric AB2.0 composition to optimize their hydrogen storage behaviours and performances as the alloy anodes of nickel metal hydride batteries. AB2-xLa0.03 Laves type alloys (A = Ti0.15Zr0.85; B = Mn0.64–0.69V0.11–0.119Fe0.11–0.119Ni1.097–1.184; x = 0, 0.05 and 0.1) were arc melted and then homogenized by annealing. The studies involved probing of the phase-structural composition by X-Ray diffraction (XRD), together with studies of the microstructural state, hydrogen absorption–desorption and thermodynamic characteristics of gas–solid reactions and electrochemical charge-discharge performance, further to the impedance spectroscopy characterization. The alloys were probed using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and XRD. These studies concluded that the alloys contained the main C15 FCC Laves type AB2 intermetallic co-existing with a secondary C14 hexagonal Laves phase and a small amount of LaNi intermetallic. The gaseous H storage capacity and electrochemical performances were found to be closely dependent on the stoichiometric compositions of the alloys. High discharge capacities approaching 500 mAh/g were achieved for the AB1.95 alloy. At 500 mA/g current density, the discharge capacity was maintained as high as 80%, with very low capacity retention after 500 cycles. The alloy which had the highest capacity retention after 500 cycles was found to be AB2.0 alloy. Furthermore, AB2.0 alloy showed an excellent cyclic stability together with a high hydrogen diffusion coefficient. Studies of hydrogen diffusion coefficients showed that annealing enhanced the H diffusion rates allowing advanced performance at high discharge current densities. This has been related to a higher content of C15 Laves compound which allows to reach a higher H mobility in contrast with higher storage capacity observed for the C14 Laves type polymorph.

• Lv, Peng; Guzik, Matylda N.; Sartori, Sabrina & Huot, Jacques (2019). Effect of ball milling and cryomilling on the microstructure and first hydrogenation properties of TiFe + 4 wt.% Zr alloy. Journal of Materials Research and Technology (JMR&T). ISSN 2238-7854. 8(2), s. 1828–1834. doi: 10.1016/j.jmrt.2018.12.013. Fulltekst i vitenarkiv Vis sammendrag

  In this paper, we report the microstructure and first hydrogenation properties of TiFe cast with 4 wt.% of Zr. Measurements were made in as-cast state and after processing by ball milling and cryomilling. It was found that ball milling and cryomilling significantly reduced the particle/crystallite sizes with most of the reduction occurring during the first 15 min of milling. While the cryomilled sample did not absorb any hydrogen, ball milling improved the initial kinetics of processed powders compared with the as-cast sample. However it also reduced the hydrogen storage capacity. The observed increased kinetics was likely caused by the reduction of crystallite sizes with longer ball milling times. However, the longer ball milling times might also be the reason of the capacity loss due to formation of new grain boundaries. Faster kinetics was not due to a change in the rate-limiting step, as all kinetics curves were fitted with the 3D growth, diffusion controlled with decreasing interface velocity model.

• Colbe, Jose Bellosta von; Ares, Jose-Ramón; Barale, Jussara; Baricco, Marcello; Buckley, Craig & Capurso, Giovanni [Vis alle 27 forfattere av denne artikkelen] (2019). Application of Hydrides in Hydrogen Storage and Compression: Achievements, Outlook and Perspectives. International Journal of Hydrogen Energy. ISSN 0360-3199. 44(15), s. 7780–7808. doi: 10.1016/j.ijhydene.2019.01.104. Fulltekst i vitenarkiv Vis sammendrag

  Metal hydrides are known as a potential efficient, low-risk option for high-density hydrogen storage since the late 1970s. In this paper, the present status and the future perspectives of the use of metal hydrides for hydrogen storage are discussed. Since the early 1990s, interstitial metal hydrides are known as base materials for Ni – metal hydride rechargeable batteries. For hydrogen storage, metal hydride systems have been developed in the 2010s [1] for use in emergency or backup power units, i. e. for stationary applications. With the development and completion of the first submarines of the U212 A series by HDW (now Thyssen Krupp Marine Systems) in 2003 and its export class U214 in 2004, the use of metal hydrides for hydrogen storage in mobile applications has been established, with new application fields coming into focus. In the last decades, a huge number of new intermetallic and partially covalent hydrogen absorbing compounds has been identified and partly more, partly less extensively characterized. In addition, based on the thermodynamic properties of metal hydrides, this class of materials gives the opportunity to develop a new hydrogen compression technology. They allow the direct conversion from thermal energy into the compression of hydrogen gas without the need of any moving parts. Such compressors have been developed and are nowadays commercially available for pressures up to 200 bar. Metal hydride based compressors for higher pressures are under development. Moreover, storage systems consisting of the combination of metal hydrides and high-pressure vessels have been proposed as a realistic solution for on-board hydrogen storage on fuel cell vehicles. In the frame of the “Hydrogen Storage Systems for Mobile and Stationary Applications” Group in the International Energy Agency (IEA) Hydrogen Task 32 “Hydrogen-based energy storage”, different compounds have been and will be scaled-up in the near future and tested in the range of 500 g to several hundred kg for use in hydrogen storage applications.

• Wijayanti, Ika Dewi; Mølmen, Live; Denys, Roman Volodymyrovich; Nei, Jean; Gorsse, Stéphane & Young, Kwo [Vis alle 8 forfattere av denne artikkelen] (2019). The electrochemical performance of melt-spun C14-Laves type TiZr-based alloy. International Journal of Hydrogen Energy. ISSN 0360-3199. 45(2), s. 1297–1303. doi: 10.1016/j.ijhydene.2019.02.093. Fulltekst i vitenarkiv
• Guzik, Matylda N.; Schrade, Matthias; Tofan, Raluca; Carvalho, Patricia Almeida; Berland, Kristian & Sørby, Magnus Helgerud [Vis alle 9 forfattere av denne artikkelen] (2019). Long- and short-range structures of Ti1-xHfxNi1.0/1.1Sn half-Heusler compounds and their electric transport properties. CrysteEngComm. 21, s. 3330–3342. doi: 10.1039/c9ce00046a. Fulltekst i vitenarkiv
• Wijayanti, Ika Dewi; Mølmen, Live; Denys, Roman Volodymyrovich; Nei, Jean; Gorsse, Stéphane & Guzik, Matylda N. [Vis alle 8 forfattere av denne artikkelen] (2019). Studies of Zr-based C15 type metal hydride battery anode alloys prepared by rapid solidification. Journal of Alloys and Compounds. ISSN 0925-8388. 804, s. 527–537. doi: 10.1016/j.jallcom.2019.06.324. Fulltekst i vitenarkiv Vis sammendrag

  The objective of the present work was to study an interrelation between the conditions of the rapid solidification casting and electrochemical properties of a C15 Laves-type Zr-based metal hydride battery anode alloy. A 7-component overstoichiometric with B/A>2 alloy (Ni + Mn + V + Fe/Zr + Ti + La = 2.078) was Zr- and Ni-rich. Melt spinning was performed using as cast mother ingot at different rotation speeds of 5, 16.5, and 33 Hz with a 20-cm diameter Cu cooling wheel. The phase composition and morphology of the ribbons were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) along with X-ray energy dispersive spectroscopy (EDS). Partial Mn vaporization took place during the melt spinning and became more pronounced with the increase in the quenching rate at higher wheel rotation speeds. The SEM study showed a successful refinement and a more homogeneous distribution of La in the melt-spun alloys. However, the alloys demonstrated a more difficult activation performance as compared to the as-cast sample which was associated with introduction of Zr into the composition of the secondary La-and Ni-rich phase when quenching the melt. Presence of Zr in the secondary phase results in inferior rate of its hydrogenation. The formed during the rapid solidification (La,Zr) (Ni,Mn) secondary phase also contained a significant amount of oxygen additionally worsening the activation performance. The grain size gradually decreased from 3.5 μm in the as-cast alloy to approximately 250 nm for the melt spun sample obtained at the highest cooling rate. The two-phase alloys contained a mixture of two Laves type intermetallics, C15 and C14 ones. The abundance of the secondary C14 phase decreased with increase of the cooling rate as compared to the as-cast sample. The electrochemical performance was significantly affected by the compositional and microstructural changes associated with the variation in the cooling rate. The highest electrochemical discharge capacity of 414 mAh/g was obtained for the 16.5 Hz melt spun rate because of an optimized composition of the Laves phase. Furthermore, the diffusion coefficient of hydrogen in this alloy was the highest in a full state of charge, which indicates that faster hydrogen diffusion and shorter hydrogen diffusion paths were achieved via an application of the rapid solidification process. An optimization of the rapid solidification conditions is required to improve an activation behavior of the studied Laves types metal hydride anode alloys.

• Guzik, Matylda N.; Mohtadi, Rana & Sartori, Sabrina (2019). Lightweight complex metal hydrides for Li-, Na-, and Mg-based batteries. Journal of Materials Research. ISSN 0884-2914. 34(6), s. 877–904. doi: 10.1557/jmr.2019.82. Fulltekst i vitenarkiv Vis sammendrag

  Energy density and safety are the main factors that govern the development of the rechargeable battery technology. Currently, batteries beyond typical Li-ion batteries such as those based on solid-state electrolytes (SSEs) or other active elements (e.g., Na or Mg) are being examined as alternatives. For example, SSEs that would enable stable and reliable operation of all-solid-state Li-, Na-, and Mg-based batteries, with preferably improved capacity, are considered to be one of the most desired inventions. Lightweight complex metal hydrides are a family of solid compounds that were recently discovered to have extraordinary ionic conductivities and, in some cases, electrochemical properties that enabled battery reversibility. Consequently, they have become one of the promising electrolyte materials for future development of electrochemical storage devices. In this work, we present an overview of a wide range of lightweight hydride-based materials that could be used as electrolytes and/or anodes for mono-/divalent batteries and have a pivotal role in the implementation of new technological solutions in the field of electrochemistry.

• Guzik, Matylda N.; Echevarria-Bonet, Cristina; Riktor, Marit Dalseth; Carvalho, Patricia Almeida; Gunnæs, Anette Eleonora & Sørby, Magnus Helgerud [Vis alle 7 forfattere av denne artikkelen] (2018). Half-Heusler phase formation and Ni atom distribution in M-Ni-Sn (M = Hf, Ti, Zr) systems. Acta Materialia. ISSN 1359-6454. 148, s. 216–224. doi: 10.1016/j.actamat.2018.01.019. Fulltekst i vitenarkiv
• Sartori, Sabrina; Guzik, Matylda N.; Knudsen, Kenneth Dahl; Sørby, Magnus Helgerud; Jr., Joseph A. Teprovich, & Zidan, Ragaiy [Vis alle 7 forfattere av denne artikkelen] (2018). Stability and Phase Formation in the (Li/Na)6C60–H Systems Studied by Neutron Scattering. Journal of Physical Chemistry C. ISSN 1932-7447. 122(32), s. 18346–18355. doi: 10.1021/acs.jpcc.8b05977. Fulltekst i vitenarkiv Vis sammendrag

  Small-angle neutron scattering combined with powder neutron diffraction was employed to study the phase formation upon absorption/desorption of hydrogen gas in Li- and Na-intercalated fullerides. The comparative system analysis, addressing changes in the sample phase compositions and the morphology of powders, revealed a higher degree of complexity in the Na-based samples. Results also showed that the disappearance of crystalline lithium/sodium hydride during desorption was accompanied by an increased surface roughness in both systems, most likely because of the formation of a local surface strain. Furthermore, an increased specific internal surface of the studied materials upon subsequent deuterium absorption/desorption cycles was demonstrated. This could indicate moderate fracturing of crystallites.

• Guzik, Matylda N.; Lang, Julien; Huot, Jacques & Sartori, Sabrina (2017). Effect of Al presence and synthesis method on phase composition of the hydrogen absorbing La–Mg–Ni-based compounds. International Journal of Hydrogen Energy. ISSN 0360-3199. 42(51), s. 30135–30144. doi: 10.1016/j.ijhydene.2017.10.062. Fulltekst i vitenarkiv Vis sammendrag

  Results for (La,Mg)Ni3.5 and (La,Mg)(Ni,Al)3.5 systems synthesized by metallurgical and mechanochemical techniques are reported. Powder X-ray and neutron diffraction combined with Rietveld refinements and profile analysis show that depending on the applied synthesis method various structurally related phases can be obtained for the same nominal composition. The hexagonal A2B7-type structure incorporating aluminum, with the refined composition La0.77Mg0.23Ni3.41Al0.09, has been identified. Al atoms occupy 12% of the 6h site within the LaNi5 slabs. This intermetallic phase absorbs hydrogen (deuterium) when exposed to 10 bar of H2 (D2) gas at room temperature. The H(D)-containing phase expands isotropically and retains the original symmetry of the parent compound. © 2017. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/

• Guzik, Matylda Natalia; Golasinski, Karol M.; Pedrosa, F.J.; Jenus, Petra; Bollero, Alberto & Hauback, Bjørn [Vis alle 7 forfattere av denne artikkelen] (2017). Influence of ultra-short cryomilling on the microstructural and magnetic properties of cobalt ferrite. Journal of Alloys and Compounds. ISSN 0925-8388. 721, s. 440–448. doi: 10.1016/j.jallcom.2017.05.290. Fulltekst i vitenarkiv
• Schrade, Matthias; Berland, Kristian; Eliassen, Simen Nut Hansen; Guzik, Matylda Natalia; Echevarria-Bonet, Cristina & Sørby, Magnus Helgerud [Vis alle 13 forfattere av denne artikkelen] (2017). The role of grain boundary scattering in reducing the thermal conductivity of polycrystalline XNiSn (X=Hf, Zr, Ti) half-Heusler alloys. Scientific Reports. 7. doi: 10.1038/s41598-017-14013-8. Fulltekst i vitenarkiv Vis sammendrag

  Thermoelectric application of half-Heusler compounds suffers from their fairly high thermal conductivities. Insight into how effective various scattering mechanisms are in reducing the thermal conductivity of fabricated XNiSn compounds (X = Hf, Zr, Ti, and mixtures thereof) is therefore crucial. Here, we show that such insight can be obtained through a concerted theory-experiment comparison of how the lattice thermal conductivity κLat(T) depends on temperature and crystallite size. Comparing theory and experiment for a range of Hf0.5Zr0.5NiSn and ZrNiSn samples reported in the literature and in the present paper revealed that grain boundary scattering plays the most important role in bringing down κLat, in particular so for unmixed compounds. Our concerted analysis approach was corroborated by a good qualitative agreement between the measured and calculated κLat of polycrystalline samples, where the experimental average crystallite size was used as an input parameter for the calculations. The calculations were based on the Boltzmann transport equation and ab initio density functional theory. Our analysis explains the significant variation of reported κLat of nominally identical XNiSn samples, and is expected to provide valuable insights into the dominant scattering mechanisms even for other materials.

• Pedrosa, F.J.; Rial, J.; Golasinski, K.M.; Guzik, Matylda Natalia; Quesada, A. & Fernández, J.F. [Vis alle 9 forfattere av denne artikkelen] (2016). Towards high performance CoFe2O4 isotropic nanocrystalline powder for permanent magnet applications. Applied Physics Letters. ISSN 0003-6951. 109(22). doi: 10.1063/1.4969064. Fulltekst i vitenarkiv
• Guzik, Matylda N.; Deledda, Stefano; Sørby, Magnus Helgerud; Yartys, Volodymyr & Hauback, Bjørn (2015). New FCC Mg-Zr and Mg-Zr-ti deuterides obtained by reactive milling. Journal of Solid State Chemistry. ISSN 0022-4596. 226, s. 237–242. doi: 10.1016/j.jssc.2015.03.005. Fulltekst i vitenarkiv
• Zavorotynska, Olena; Deledda, Stefano; Vitillo, Jenny G.; Saldan, Ivan; Guzik, Matylda Natalia & Baricco, Marcello [Vis alle 9 forfattere av denne artikkelen] (2015). Combined X-ray and Raman studies on the effect of cobalt additives on the decomposition of magnesium borohydride. Energies. 8(9), s. 9173–9190. doi: 10.3390/en8099173. Fulltekst i vitenarkiv Vis sammendrag

  Magnesium borohydride (Mg(BH4)2) is one of the most promising hydrogen storage materials. Its kinetics of hydrogen desorption, reversibility, and complex reaction pathways during decomposition and rehydrogenation, however, present a challenge, which has been often addressed by using transition metal compounds as additives. In this work the decomposition of Mg(BH4)2 ball-milled with CoCl2 and CoF2 additives, was studied by means of a combination of several in-situ techniques. Synchrotron X-ray diffraction and Raman spectroscopy were used to follow the phase transitions and decomposition of Mg(BH4)2. By comparison with pure milled Mg(BH4)2, the temperature for the γ → ε phase transition in the samples with CoF2 or CoCl2 additives was reduced by 10–45 °C. In-situ Raman measurements showed the formation of a decomposition phase with vibrations at 2513, 2411 and 766 cm−1 in the sample with CoF2. Simultaneous X-ray absorption measurements at the Co K-edge revealed that the additives chemically transformed to other species. CoF2 slowly reacted upon heating till ~290 °C, whereas CoCl2 transformed drastically at ~180 °C.

• Kalantzopoulos, Georgios N.; Guzik, Matylda N.; Deledda, Stefano; Heyn, Richard H; Muller, Jiri & Hauback, Bjørn (2014). Destabilization effect of transition metal fluorides on sodium borohydride. Physical Chemistry, Chemical Physics - PCCP. ISSN 1463-9076. 16(38), s. 20483–20491. doi: 10.1039/c4cp02899f. Fulltekst i vitenarkiv Vis sammendrag

  The effect of transition metal fluorides on the decomposition of NaBH4 has been investigated for NaBH4 ball milled with TiF3, MnF3 or FeF3. The compounds were examined by thermal programmed desorption with residual gas analysis, thermo gravimetric analysis and volumetric measurements using a Sieverts-type apparatus. The phase formation process during thermal decomposition was studied by in situ synchrotron radiation powder X-ray diffraction on the as-milled powders. NaBF4 was among the products in all mechano-chemical reactions. 11B-NMR spectra analysis gave NaBF4:NaBH4 ratios of 1:150 for Na–Ti, 1:40 for Na–Mn, and 1:10 for Na–Fe. Pure NaBH4 possessed a hydrogen release onset temperature of 430 °C. The hydrogen release in the NaBH4–MnF3 system began as low as 130 °C. FeF3 decreased the onset temperature to 161 °C and TiF3 to 200 °C. TiF3 reacted completely with NaBH4 below 320 °C. All the examined systems have negligible emissions of diborane species. H-sorption studies performed at selected temperatures above 300 °C exhibited relatively fast desorption kinetics. Partial hydrogen re-absorption was observed for the Na–Mn and Na–Fe samples.

• Guzik, Matylda N.; Hauback, Bjørn & Yvon, Klaus (2012). Hydrogen atom distribution and hydrogen induced site depopulation for the La2-xMgxNi7-H system. Journal of Solid State Chemistry. ISSN 0022-4596. 186, s. 9–16. doi: 10.1016/j.jssc.2011.11.026. Fulltekst i vitenarkiv
• Guzik, Matylda N.; Hauback, B. C. & Yvon, Klaus (2008). Repulsive carbon–deuterium interactions in zirconium and titanium carbodeuterides. Journal of Alloys and Compounds. ISSN 0925-8388. doi: 10.1016/j.jallcom.2007.07.085. Fulltekst i vitenarkiv
• Sartori, Sabrina; Opalka, Susanne M.; Martin, Løvvik Ole; Guzik, Matylda N.; Tang, Xia & Hauback, B. C. (2008). Experimental studies of α-AlD3 and α′-AlD3 versus first-principles modelling of the alane isomorphs. Journal of Materials Chemistry. ISSN 0959-9428. doi: 10.1039/B718896J. Fulltekst i vitenarkiv
• Guzik, Matylda N.; Romanczyk, Piotr P. & Wlodarczyk, Andrzej (2007). Redox activity of bimetallic complexes based on tris(3,5-dimethylpyrazolyl)borato molybdenum(II) and tungsten(II) nitrosyls. Complexes derived from ethane-1,2-diol and the crystal structure of anti-[Mo(NO){HB(3,5Me2C3HN2)3}(OCH 2CH2O)]2·4CHCl3. Polyhedron. ISSN 0277-5387. doi: 10.1016/j.poly.2006.10.004. Fulltekst i vitenarkiv

Se alle arbeider i NVA

• Kohfeldt, Anja; Knutsen, Elise Wright; Guzik, Matylda N. & Perez, Jose Miguel Gonzalez (2026). Project-based Learning in the Space Systems Master’s Degree Programme at the University of Oslo. doi: 10.14459/2026md1857555. Fulltekst i vitenarkiv Vis sammendrag

  In 2023 the University of Oslo (UiO), Department of Technology Systems (ITS) established a new master’s degree study programme in Space Systems. From the beginning we focused on a system approach, setting space technology in the context of their operational environment and applications. Thus, we incorporate not only technology-focused theoretical lectures but also a diverse range of practical experiences and exercises, workshops in systems engineering, and numerous project opportunities. A highlight of our programme is the project course in the second semester. In a cooperation with Andøya Space Education, students develop a mini-mission concept, design the payload, build, integrate, test, launch the probe, and analyse the collected data. Throughout this process, they meet all standard milestones, gaining valuable experience in documentation, presentation skills, teamwork, and deliverables management under time constraints. To deepen specific field knowledge and foster engagement, we recommend a two-semester master’s thesis project, during which students profit from the research environment at ITS and the Centre for Space Sensors and Systems (CENSSS), with collaborating institutions and industry partners. CENSSS is currently developing CENSSAT-1, a 16U CubeSat for monitoring the interaction between solar activity and Earth’s atmosphere. This CubeSat mission primarily involves PhD fellows and master’s students and offers a wide array of relevant master’s thesis topics, providing direct experience with real space mission development. In this paper, we share our approach to hands-on education within the master’s programme in Space Systems and summarise our insights gained over almost three years of operation.

• Javed, Muhammad Shahzad; Fossheim, Karin; Guzik, Matylda; Seibt, Beate & Zyringer, Marianne (2025). How can youth perspectives shape Norway's 2050 electricity system? doi: 10.5194/egusphere-egu25-18405. Fulltekst i vitenarkiv Vis sammendrag

  While participatory research seeks to engage stakeholders, young people&#8212;who will bear the consequences of recent policy decisions&#8212;remain largely overlooked, as evidenced by climate strikes and environmental movements highlighting their growing distrust in the energy transition process. In this interdisciplinary study, we conducted workshops with students to develop diverse scenarios assessing the impact of pupils&#8217; socio-techno-economic choices on the snapshots of a 2050 net-zero electricity system for Norway. We use those scenarios in an electricity system model for Norway. Our results indicate that pupil landscape preferences reduce Norway&#8217;s land-based capacity potential by more than half, resulting in an approximate 9% increase in the Levelized Cost of Electricity, from 790 to 880 NOK/MWh. Given that 68% of pupils favored offshore wind, integrating their technological preferences reduces the onshore wind portfolio from 33 GW to nearly zero in the most conservative scenario, accompanied by a reduction in solar capacity from 30 GW to 6 GW. Regional preferences lead to a concentrated allocation of new offshore wind installations predominantly in the west and south of Norway, areas with existing hydropower, potentially inducing local socio-political issues. Moreover, pupils supported new transmission lines and electricity trading under the condition of self-sufficiency, reducing system costs by approximately 8%, providing a win-win scenario for Norway and Europe. The cumulative impact of pupil choices significantly depends on how they are prioritized. The median system cost for achieving a net-zero emission system could likely be reduced by 7%-8% if Norway prioritizes investments in transmission infrastructure locally and through interconnections with neighboring countries while honoring youth preferences. Building on evolving participatory research, this study not only provides a framework for fostering mutual understanding with youth but also demonstrates their capacity for meaningful participation in energy transition discussions, thus promoting an inclusive and swift energy transition.

• Lu, Yang; Sednev-Lugovets, Anton; Carvalho, Patricia Almeida; Guzik, Matylda N.; Dunkel, Kristina G & Austrheim, Håkon Olaf [Vis alle 7 forfattere av denne artikkelen] (2023). Dypingite revisited. Norsk Mineralsymposium. 2023, s. 23–30. Fulltekst i vitenarkiv
• Friis, Henrik; Lu, Yang; Sednev-Lugovets, Anton; Carvalho, Patricia Almeida; Guzik, Matylda N. & Dunkel, Kristina G [Vis alle 7 forfattere av denne artikkelen] (2023). Dypingitt - Nytt 'liv' i gamle gruver. Fulltekst i vitenarkiv
• Sednev-Lugovets, Anton; Lu, Yang; Vistad, Ørnulv Bjørnsson; Austrheim, Håkon; Friis, Henrik & Carvalho, Patricia Almeida [Vis alle 7 forfattere av denne artikkelen] (2023). Magnesium Hydroxy Carbonate Hydrates—Nature-Inspired Water Filters for Heavy Metal Sequestration. Fulltekst i vitenarkiv Vis sammendrag

  Magnesium hydroxy carbonate hydrates: Nature-inspired water filters for heavy metal sequestration Anton Sednev-Lugovets1, Yang Lu2, Ørnulv Vistad3, Håkon Austrheim4, Henrik Friis2, Patricia A. Carvalho3 and Matylda N. Guzik1 1 University of Oslo, Department of Technology Systems, Kjeller, Norway 2 University of Oslo, Natural History Museum, Oslo, Norway 3 SINTEF Industry, Oslo, Norway 4 University of Oslo, Department of Geosciences, Oslo, Norway The climate change, growing world population, together with a widespread use of chemicals in industry and our everyday life, are projected to reduce water availability in sufficient quantity and quality. Heavy metal contaminations have a seriously damaging impact on the quality of water bodies, imposing a great burden on downstream users and ecosystems. Although, natural materials, such as charcoal, sand and diatomaceous earth, have been already incorporated into modern water filtration systems ( ), there is still a great need for highly efficient and environmentally sustainable sorbents. Motivated by this challenge, we focus our research on investigation of nature-inspired sustainable functional materials and their application in water filter technologies. Magnesium hydroxy carbonate hydrates are a relatively small group of naturally formed minerals that have been widely investigated for large-scale CO2 sequestration. However, our recent study has shown that these compounds can also effectively remove heavy metals (e.g., Cr, Cd, Cu, Pb, Ni ( )) from water and act as water filters ( , ). Two members of this mineral family: 1) dypingite (named in ’70s by Gunnar Raade, after the Dypingdal serpentine-magnesite deposit in Norway), and yet 2) unnamed compound (hereafter referred to as UPh, a new crystalline phase identified by us while studying dypingite samples), deserve particular attention due to their unique desert rose morphology. The term “desert rose” designates self-assembled microstructures with clusters organized into fanning platelets. These 3D configurations exhibit hierarchical features that span across multiple length scales and present high specific surface area, which are crucial for many applications including sorption. Despite the remarkable sorption performance, information about the dypingite and UPh structural properties is surprisingly limited. Even though, the naturally occurring dypingite was a subject of several investigations ( , ), the available data on the material chemical composition, in particular water content, and structural features are inconsistent. The synthetic dypingite minerals has also been obtained but none of the applied approaches resulted in the formation of desert rose-like microstructures, occurring exclusively in naturally formed compounds. For better understanding of phenomena behind the physical & chemical performance of both minerals, the systematic and detailed material analysis is indispensable. To partly fill this gap, we have been performing comprehensive structural, microstructural and functional studies on natural and synthetic samples of both minerals that allow us: i) to define optimum synthesis conditions for the formation of materials with desert rose morphologies, ii) to determine relationship between the material structural/microstructural characteristics and its heavy metal sorption capacity, iii) to define the compound stability range, and iv) to identify unique powder X-ray diffraction patterns of both phases, in order to solve their crystal structures.

• Lu, Yang; Sednev-Lugovets, Anton; Carvalho, Patricia Almeida; Guzik, Matylda N.; Dunkel, Kristina G & Austrheim, Håkon Olaf [Vis alle 7 forfattere av denne artikkelen] (2023). Dypingite series defined by the content of molecular H2O. Fulltekst i vitenarkiv
• Guzik, Matylda N.; Sednev-Lugovets, Anton; Carvalho, Patricia Almeida; Friis, Henrik; Lu, Yang & Vistad, Ørnulv Bjørnsson [Vis alle 7 forfattere av denne artikkelen] (2023). Sustainable materials & green technologies for renewable energy systems / Nature-inspired filters for sequestration of heavy metals. Fulltekst i vitenarkiv
• Guzik, Matylda N. & Lin, Yuan-Chih (2023). Sustainable materials and green technologies for renewable energy systems / Green hydrogen production and storage. Fulltekst i vitenarkiv
• Chatzitakis, Athanasios; Zhu, Junjie; Gudmundsdottir, Jonina Björg; Strandbakke, Ragnar; Both, Kevin Gregor & Aarholt, Thomas [Vis alle 12 forfattere av denne artikkelen] (2022). A monolithic and noble metal-free photoelectrochemical device of minimal engineering for efficient, unassisted water splitting. Fulltekst i vitenarkiv
• Guzik, Matylda N.; Lin, Yuan-Chih; Solarska, Renata & Bienkowski, Krzysztof (2022). A photoelectrochemical device with the metal hydride-based hydrogen storage. Fulltekst i vitenarkiv
• Sednev-Lugovets, Anton; Lu, Yang; Carvalho, Patricia Almeida; Vistad, Ørnulv Bjørnsson; Friis, Henrik & Austrheim, Håkon Olaf [Vis alle 7 forfattere av denne artikkelen] (2022). Dypingite: The phase identification and transformation. Fulltekst i vitenarkiv Vis sammendrag

  Dypingite is a naturally occurring mineral, with an empirical formula Mg₅(CO₃)₄(OH)₂·5H₂O, and a member of the hydrocarbonate mineral group. It was named in 1970 by Gunnar Raade, after the Dypingdal serpentine-magnesite deposit in Norway ( ). Recently, it was reported that this mineral can effectively remove heavy metals (e.g., Cr, Cd, Cu, Pb, Ni ( )) from water and cause their long-term immobilisation ( ). It is expected that the unique desert rose morphology of the compound or/and peculiarities of its crystal structure (Figure 1) are the reasons of the dypingite remarkable sorption properties. Despite the fact that this mineral has been known for 50 years, the information about its unit cell parameters, or even Bragg peak positions, is inconsistent and surprisingly limited. To partly fill this gap, we have been performing comprehensive structural and microstructural studies on the natural and synthetic dypingite powder samples to: i) identify a crystalline phase called dypingite; ii) correctly index powder X-ray diffraction (PXD) patterns so as to determine the compound unit cell parameters and to solve its crystal structure; iii) investigate the dypingite phase transformation occurring upon the compound hydration/dehydration.

• Sednev-Lugovets, Anton; Lu, Yang; Carvalho, Patricia Almeida; Vistad, Ørnulv Bjørnsson; Friis, Henrik & Austrheim, Håkon Olaf [Vis alle 7 forfattere av denne artikkelen] (2022). Dypingite: The phase identification and transformation. Fulltekst i vitenarkiv Vis sammendrag

  Dypingite is a naturally occurring mineral, with an empirical formula Mg₅(CO₃)₄(OH)₂·5H₂O, and a member of the hydrocarbonate mineral group. It was named in 1970 by Gunnar Raade, after the Dypingdal serpentine-magnesite deposit in Norway ( ). Recently, it was reported that this mineral can effectively remove heavy metals (e.g., Cr, Cd, Cu, Pb, Ni ( )) from water and cause their long-term immobilisation ( ). It is expected that the unique desert rose morphology of the compound or/and peculiarities of its crystal structure (Figure 1) are the reasons of the dypingite remarkable sorption properties. Despite the fact that this mineral has been known for 50 years, the information about its unit cell parameters, or even Bragg peak positions, is inconsistent and surprisingly limited. To partly fill this gap, we have been performing comprehensive structural and microstructural studies on the natural and synthetic dypingite powder samples to: i) identify a crystalline phase called dypingite; ii) correctly index powder X-ray diffraction (PXD) patterns so as to determine the compound unit cell parameters and to solve its crystal structure; iii) investigate the dypingite phase transformation occurring upon the compound hydration/dehydration.

• Rahman, Jamil Ur; Carvalho, Patricia Almeida; Guzik, Matylda N.; Soltani, Nayereh; Gunnæs, Anette Eleonora & Karlsena, Ole Bjørn [Vis alle 7 forfattere av denne artikkelen] (2021). Synthesis and crystal structure of Sb-based high entropy alloys. Fulltekst i vitenarkiv
• Guzik, Matylda N.; Echevarria-Bonet, Cristina; Sørby, Magnus Helgerud & Hauback, Bjørn (2017). Half-Heusler Phase Formation and Ni atom distribution in M-Ni-Sn (M = Hf, Ti, Zr) System. Fulltekst i vitenarkiv
• Guzik, Matylda N.; Schrade, Matthias; Tofan, Raluca; Berland, Kristian; Gunnæs, Anette Eleonora & Persson, Clas [Vis alle 8 forfattere av denne artikkelen] (2017). Structural Investigation of Ti1-xHfxNiySn Half-Heusler Compounds. Fulltekst i vitenarkiv
• Schrade, Matthias; Berland, Kristian; Guzik, Matylda Natalia; Løvvik, Ole Martin & Finstad, Terje (2017). Why does the thermal conductivity of XNiSn vary for nominally identical samples? Fulltekst i vitenarkiv
• Berland, Kristian; Eliassen, Simen Nut Hansen; Schrade, Matthias; Tofan, Raluca; Guzik, Matylda Natalia & Gunnæs, Anette Eleonora [Vis alle 11 forfattere av denne artikkelen] (2017). Using theory to understand thermoelectric materials. Fulltekst i vitenarkiv
• Strandbakke, Ragnar; Vøllestad, Einar; Norby, Truls Eivind; Sartori, Sabrina; Guzik, Matylda Natalia & Lang, Julien (2017). Hydration and structural properties of mixed conductor Ba1‑xGd0.8La0.2+xCo2O6-δ (BGLC). Fulltekst i vitenarkiv
• Strandbakke, Ragnar; Vøllestad, Einar; Norby, Truls Eivind; Sartori, Sabrina; Guzik, Matylda Natalia & Lang, Julien (2017). Hydration and structural properties of mixed conductor Ba1‑xGd0.8La0.2+xCo2O6-δ (BGLC). Fulltekst i vitenarkiv
• Schrade, Matthias; Echevarria-Bonet, Cristina; Guzik, Matylda Natalia; Tofan, Raluca; Gunnæs, Anette Eleonora & Eliassen, Simen Nut Hansen [Vis alle 10 forfattere av denne artikkelen] (2016). Thermal properties of XNiSN (X = Ti, Zr, Hf) half Heusler alloys. Fulltekst i vitenarkiv
• Guzik, Matylda Natalia (2016). Influence of Phase Composition and Microstructure on Thermoelectric Properties of Half‐Heuslers. Fulltekst i vitenarkiv
• Echevarria-Bonet, Cristina; Guzik, Matylda Natalia; Sørby, Magnus Helgerud & Hauback, Bjørn (2016). Composition of n-type Half-Heusler Compounds by SR-PXD. Fulltekst i vitenarkiv
• Zorogiannidis, Charilaos; Sartori, Sabrina & Guzik, Matylda N. (2021). Ti1.1CrMn and its hydrides for the application in thermal hydrogen compression. Universitetet i Oslo. Fulltekst i vitenarkiv Vis sammendrag

  One of the methods to compress hydrogen gas is through the utilization of thermal metal hydride hydrogen compressors (TMHHCs) The present work aims to investigate the structural and thermodynamic properties of the Ti1.1CrMn intermetallic compound for the application in metal hydride-based hydrogen compression technologies developed for operation at high pressures (&gt;350 bar). Three powder samples of intermetallics, with the same nominal composition of Ti1.1CrMn, have been studied in collaboration with Greenway Energy, LLC (USA). One of the samples was provided by Japan Metals &amp; Chemicals Co. Ltd (hereafter referred to as JMC), while the two others were fabricated by the Ames Laboratory (USA), of which one contained as-synthesized (hereafter referred to as AMES-as-cast), while the other one the annealed (hereafter referred to as AMES-annealed) material. The samples were investigated by powder X-ray diffraction (PXD) and/or pressure-composition-temperature (PCT) measurements. The PXD data of the JMC sample show the presence of a hexagonal Ti1.1CrMn phase, which is a C14 Laves phase. The powder diffraction pattern of the AMES-as-cast also confirms the formation of hexagonal Ti1.1CrMn, however with notably lower crystallinity. Interestingly, in the AMES-annealed, the presence of two hexagonal Ti1.1CrMn-based phases are clearly observed. The PCT profiles for JMC indicate a single plateau region at 35 bar (at 22oC) during the hydrogen desorption. For AMES-annealed two plateau regions at 23oC can be identified, 1st plateau at 39 bar and 2nd plateau at 78 bar. By comparing the present PXD and PCT results with the previously reported structural and thermodynamic data for Ti1.1CrMn, the second plateau in the PCT profile of AMES-annealed can be attributed to one of the identified Ti1.1CrMn-based phase, with the smaller unit cell parameters. For JMC, the plateau pressure is significantly lower (for desorption 35 bar at 22oC) than values reported in literature ( ~80 bar at 19oC). The higher hydrogen absorption and desorption pressures observed for the AMES-annealed material, as compared to JMC, are advantageous in view of its potential application in TMHHC. However, the presence of two plateau regions in this sample severely limits its usability due to the reduced amount of the desired phase available for compression of hydrogen at the required higher pressure.

Se alle arbeider i NVA