41 research outputs found

    Allmännyttans handlingsutrymme

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    Denna bok handlar om allmännyttans ställning på den svenska bostadsmarknaden. Den allmännyttiga hyresrätten har under efterkrigstiden varit en garant för en generell bostadspolitik med ambitionen om ”en bostad för alla”. Med de senaste årtiondenas marknadsinriktning av bostadsfrågorna har dock allmännyttans förutsättningar förändrats. En ny lag anger att allmännyttan både ska vara samhällsnyttig och verka utifrån affärsmässiga principer. Hur går detta ihop? Kommer allmännyttan att lyckas med denna dubbla uppgift? Boken belyser ur ett brett perspektiv de strategiska vägval som de nya förutsättningarna för med sig, inte bara för de kommunala bostadsföretagen utan också för svensk bostadspolitik framöver. Boken är resultatet av ett flervetenskapligt forskningsprojekt som har engagerat ett dussintal forskare specialiserade på olika aspekter av allmännyttans förändrade roll. Forskningsledare och redaktör för boken har varit Tapio Salonen, professor i socialt arbete vid Malmö högskola

    Marinite Li<sub>2</sub>M(SO<sub>4</sub>)<sub>2</sub> (M = Co, Fe, Mn) and Li<sub>1</sub>Fe(SO<sub>4</sub>)<sub>2</sub>: Model Compounds for Super-Super-Exchange Magnetic Interactions

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    New materials initially designed for battery electrodes are often of interest for magnetic study, because their chemical compositions include 3d transition metals. We report here on the magnetic properties of marinite phases Li<sub>2</sub>M­(SO<sub>4</sub>)<sub>2</sub> (M = Fe, Co, Mn) and Li<sub>1</sub>Fe­(SO<sub>4</sub>)<sub>2</sub>, which all order antiferromagnetically at low temperature. From neutron powder diffraction, we propose a model for their ground-state magnetic structures. The magnetism of marinite Li<sub>2</sub>M­(SO<sub>4</sub>)<sub>2</sub> compounds unambiguously results from super-super-exchange interactions; therefore, these materials can be considered as a model case for which the Goodenough–Kanamori–Anderson rules can be tested

    Magnetic Structures of Orthorhombic Li<sub>2</sub>M(SO<sub>4</sub>)<sub>2</sub> (M = Co, Fe) and Li<sub><i>x</i></sub>Fe(SO<sub>4</sub>)<sub>2</sub> (<i>x</i> = 1, 1.5) Phases

    No full text
    We report herein on the magnetic properties and structures of orthorhombic Li<sub>2</sub>M­(SO<sub>4</sub>)<sub>2</sub> (M = Co, Fe) and their oxidized phases Li<sub><i>x</i></sub>Fe­(SO<sub>4</sub>)<sub>2</sub> (<i>x</i> = 1, 1.5), which were previously studied as potential cathode materials for Li-ion batteries. The particular structure of these orthorhombic compounds (space group <i>Pbca</i>) consists of a three-dimensional network of isolated MO<sub>6</sub> octahedra enabling solely super-super-exchange interactions between transition metals. We studied the magnetic properties of these phases via temperature-dependent susceptibility measurements and applied neutron powder diffraction experiments to solve their magnetic structures. All compounds present an antiferromagnetic long-range ordering of the magnetic spins below their Néel temperature. Their magnetic structures are collinear and follow a spin sequence (+ + – – – – + +), with the time reversal associated with the inversion center, a characteristic necessary for a linear magneto-electric effect. We found that the orientation of the magnetic moments varies with the nature of M. While Li<sub>2</sub>Co­(SO<sub>4</sub>)<sub>2</sub> and Li<sub>1</sub>Fe­(SO<sub>4</sub>)<sub>2</sub> adopt the magnetic space group <i>Pb</i>′<i>c</i>′<i>a</i>′, the magnetic space group for Li<sub>2</sub>Fe­(SO<sub>4</sub>)<sub>2</sub> and Li<sub>1.5</sub>Fe­(SO<sub>4</sub>)<sub>2</sub> is <i>P</i>112<sub>1</sub>′/<i>a</i>, which might hint for a possible monoclinic distortion of their nuclear structure. Moreover we compared the orthorhombic phases to their monoclinic counterparts as well as to the isostructural orthorhombic Li<sub>2</sub>Ni­(SO<sub>4</sub>)<sub>2</sub> compound. Finally, we show that this possible magneto-electric feature is driven by the topology of the magnetic interactions

    Decoupling Cationic–Anionic Redox Processes in a Model Li-Rich Cathode via <i>Operando</i> X‑ray Absorption Spectroscopy

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    The demonstration of reversible anionic redox in Li-rich layered oxides has revitalized the search for higher energy battery cathodes. To advance the fundamentals of this promising mechanism, we investigate herein the cationic–anionic redox processes in Li<sub>2</sub>Ru<sub>0.75</sub>Sn<sub>0.25</sub>O<sub>3</sub>a model Li-rich layered cathode in which Ru (cationic) and O (anionic) are the only redox-active sites. We reveal its charge compensation mechanism and local structural evolutions by applying <i>operando</i> (and complementary <i>ex situ</i>) X-ray absorption spectroscopy (XAS). Among other local effects, the anionic-oxidation-driven distortion of the oxygen network around Ru atoms is thereby visualized. Oxidation of lattice oxygen is also directly proven via hard X-ray photoelectron spectroscopy (HAXPES). Furthermore, we demonstrate a spectroscopy-driven visualization of electrochemical reaction paths, which enabled us to neatly decouple the individual cationic–anionic <i>dQ</i>/<i>dV</i> contributions during cycling. We hence establish the redox and structural origins of all <i>dQ</i>/<i>dV</i> features and demonstrate the vital role of anionic redox in hysteresis and kinetics. These fundamental insights about Li-rich systems are crucial for improving the existing anionic-redox-based cathodes and evaluating the ones being discovered rapidly

    Magnetic Structures of Orthorhombic Li<sub>2</sub>M(SO<sub>4</sub>)<sub>2</sub> (M = Co, Fe) and Li<sub><i>x</i></sub>Fe(SO<sub>4</sub>)<sub>2</sub> (<i>x</i> = 1, 1.5) Phases

    No full text
    We report herein on the magnetic properties and structures of orthorhombic Li<sub>2</sub>M­(SO<sub>4</sub>)<sub>2</sub> (M = Co, Fe) and their oxidized phases Li<sub><i>x</i></sub>Fe­(SO<sub>4</sub>)<sub>2</sub> (<i>x</i> = 1, 1.5), which were previously studied as potential cathode materials for Li-ion batteries. The particular structure of these orthorhombic compounds (space group <i>Pbca</i>) consists of a three-dimensional network of isolated MO<sub>6</sub> octahedra enabling solely super-super-exchange interactions between transition metals. We studied the magnetic properties of these phases via temperature-dependent susceptibility measurements and applied neutron powder diffraction experiments to solve their magnetic structures. All compounds present an antiferromagnetic long-range ordering of the magnetic spins below their Néel temperature. Their magnetic structures are collinear and follow a spin sequence (+ + – – – – + +), with the time reversal associated with the inversion center, a characteristic necessary for a linear magneto-electric effect. We found that the orientation of the magnetic moments varies with the nature of M. While Li<sub>2</sub>Co­(SO<sub>4</sub>)<sub>2</sub> and Li<sub>1</sub>Fe­(SO<sub>4</sub>)<sub>2</sub> adopt the magnetic space group <i>Pb</i>′<i>c</i>′<i>a</i>′, the magnetic space group for Li<sub>2</sub>Fe­(SO<sub>4</sub>)<sub>2</sub> and Li<sub>1.5</sub>Fe­(SO<sub>4</sub>)<sub>2</sub> is <i>P</i>112<sub>1</sub>′/<i>a</i>, which might hint for a possible monoclinic distortion of their nuclear structure. Moreover we compared the orthorhombic phases to their monoclinic counterparts as well as to the isostructural orthorhombic Li<sub>2</sub>Ni­(SO<sub>4</sub>)<sub>2</sub> compound. Finally, we show that this possible magneto-electric feature is driven by the topology of the magnetic interactions

    Electrostatic Interactions versus Second Order Jahn–Teller Distortion as the Source of Structural Diversity in Li<sub>3</sub>MO<sub>4</sub> Compounds (M = Ru, Nb, Sb and Ta)

    No full text
    With the advent of layered rocksalt oxides showing anionic redox activity toward Li, there has been an increased focus on designing new rocksalt structures and, more particularly, compounds pertaining to the Li<sub>3</sub>MO<sub>4</sub> family. The structural richness of this family is nested in its ability to host many different cations, leading to the formation of superstructure patterns whose predictability is still limited. Thus, there is a need to understand the formation of such superstructures, as cationic arrangements have a crucial effect on their physical properties. Herein we propose a combined experimental and theoretical approach to understand the interactions governing cation ordering in binary systems of general composition given by Li<sub>3</sub>M<sub><i>y</i></sub>M′<sub>1–<i>y</i></sub>O<sub>4</sub> (M and M′ being Ru, Nb, Sb, and Ta). Through complementary X-ray diffraction and X-ray absorption spectroscopy techniques, we reveal a solid-solution behavior for the Li<sub>3</sub>Ru<sub><i>y</i></sub>Sb<sub>1–<i>y</i></sub>O<sub>4</sub> system, as opposed to Li<sub>3</sub>Sb<sub><i>y</i></sub>Nb<sub>1–<i>y</i></sub>O<sub>4</sub> that enlists four rocksalt structures with different cation orderings. We use DFT calculations to rationalize such a structural diversity and find that it is controlled by a delicate balance between electrostatic interactions and charge transfer due to a second order Jahn–Teller distortion. This insight provides a new viewpoint for understanding cationic arrangements in rocksalt structures and guidelines to design novel phases for applications such as Li-ion batteries or ionic conductors

    Magnetic Structures of Orthorhombic Li<sub>2</sub>M(SO<sub>4</sub>)<sub>2</sub> (M = Co, Fe) and Li<sub><i>x</i></sub>Fe(SO<sub>4</sub>)<sub>2</sub> (<i>x</i> = 1, 1.5) Phases

    No full text
    We report herein on the magnetic properties and structures of orthorhombic Li<sub>2</sub>M­(SO<sub>4</sub>)<sub>2</sub> (M = Co, Fe) and their oxidized phases Li<sub><i>x</i></sub>Fe­(SO<sub>4</sub>)<sub>2</sub> (<i>x</i> = 1, 1.5), which were previously studied as potential cathode materials for Li-ion batteries. The particular structure of these orthorhombic compounds (space group <i>Pbca</i>) consists of a three-dimensional network of isolated MO<sub>6</sub> octahedra enabling solely super-super-exchange interactions between transition metals. We studied the magnetic properties of these phases via temperature-dependent susceptibility measurements and applied neutron powder diffraction experiments to solve their magnetic structures. All compounds present an antiferromagnetic long-range ordering of the magnetic spins below their Néel temperature. Their magnetic structures are collinear and follow a spin sequence (+ + – – – – + +), with the time reversal associated with the inversion center, a characteristic necessary for a linear magneto-electric effect. We found that the orientation of the magnetic moments varies with the nature of M. While Li<sub>2</sub>Co­(SO<sub>4</sub>)<sub>2</sub> and Li<sub>1</sub>Fe­(SO<sub>4</sub>)<sub>2</sub> adopt the magnetic space group <i>Pb</i>′<i>c</i>′<i>a</i>′, the magnetic space group for Li<sub>2</sub>Fe­(SO<sub>4</sub>)<sub>2</sub> and Li<sub>1.5</sub>Fe­(SO<sub>4</sub>)<sub>2</sub> is <i>P</i>112<sub>1</sub>′/<i>a</i>, which might hint for a possible monoclinic distortion of their nuclear structure. Moreover we compared the orthorhombic phases to their monoclinic counterparts as well as to the isostructural orthorhombic Li<sub>2</sub>Ni­(SO<sub>4</sub>)<sub>2</sub> compound. Finally, we show that this possible magneto-electric feature is driven by the topology of the magnetic interactions

    Electrochemical Reduction of CO<sub>2</sub> Mediated by Quinone Derivatives: Implication for Li–CO<sub>2</sub> Battery

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    The pivotal role of CO<sub>2</sub> played in global temperature cycles has motivated the ongoing research on carbon capture and storage (CCS). Within this context, Li–CO<sub>2</sub> battery, alike the configuration of Li–O<sub>2</sub> battery, has been proposed as a novel energy storage device with the potential to reduce CO<sub>2</sub>. Nevertheless, the highly negative potential required for the electrochemical reduction of CO<sub>2</sub> adds difficulty to the achievement of energy efficient Li–CO<sub>2</sub> battery. Facilitating the electron transfer to this inert molecule, which largely dictates the discharge voltage and rate capability of a Li–CO<sub>2</sub> battery, is therefore necessary. Herein, three types of quinones have been surveyed, aiming to mediate the reduction of CO<sub>2</sub>, which is expected to result in lower overpotential than with a direct electron transfer. We demonstrate by cyclic voltammetry that, in the presence of quinones, CO<sub>2</sub> reduction proceeds through an intermolecular interaction between CO<sub>2</sub> and quinone dianion. Importantly, such catalytic CO<sub>2</sub> reduction reaction is associated with the molecular structure of quinones, the supporting cation (e.g., Li<sup>+</sup>), and the electrolyte solvent. Furthermore, Li–CO<sub>2</sub> battery mediated by 2,5-di<i>tert</i>-butyl-1,4-benzoquinone with Li<sub>2</sub>CO<sub>3</sub> as the ultimate discharge product is achieved. This study validates the concept of using quinones as chemical catalysts to promote CO<sub>2</sub> reduction in Li–CO<sub>2</sub> battery. Besides, battery performance and NMR analysis together suggest that side reactions involving quinone itself and other cell components occur

    Electrostatic Interactions versus Second Order Jahn–Teller Distortion as the Source of Structural Diversity in Li<sub>3</sub>MO<sub>4</sub> Compounds (M = Ru, Nb, Sb and Ta)

    No full text
    With the advent of layered rocksalt oxides showing anionic redox activity toward Li, there has been an increased focus on designing new rocksalt structures and, more particularly, compounds pertaining to the Li<sub>3</sub>MO<sub>4</sub> family. The structural richness of this family is nested in its ability to host many different cations, leading to the formation of superstructure patterns whose predictability is still limited. Thus, there is a need to understand the formation of such superstructures, as cationic arrangements have a crucial effect on their physical properties. Herein we propose a combined experimental and theoretical approach to understand the interactions governing cation ordering in binary systems of general composition given by Li<sub>3</sub>M<sub><i>y</i></sub>M′<sub>1–<i>y</i></sub>O<sub>4</sub> (M and M′ being Ru, Nb, Sb, and Ta). Through complementary X-ray diffraction and X-ray absorption spectroscopy techniques, we reveal a solid-solution behavior for the Li<sub>3</sub>Ru<sub><i>y</i></sub>Sb<sub>1–<i>y</i></sub>O<sub>4</sub> system, as opposed to Li<sub>3</sub>Sb<sub><i>y</i></sub>Nb<sub>1–<i>y</i></sub>O<sub>4</sub> that enlists four rocksalt structures with different cation orderings. We use DFT calculations to rationalize such a structural diversity and find that it is controlled by a delicate balance between electrostatic interactions and charge transfer due to a second order Jahn–Teller distortion. This insight provides a new viewpoint for understanding cationic arrangements in rocksalt structures and guidelines to design novel phases for applications such as Li-ion batteries or ionic conductors

    Magnetic Structures of Orthorhombic Li<sub>2</sub>M(SO<sub>4</sub>)<sub>2</sub> (M = Co, Fe) and Li<sub><i>x</i></sub>Fe(SO<sub>4</sub>)<sub>2</sub> (<i>x</i> = 1, 1.5) Phases

    No full text
    We report herein on the magnetic properties and structures of orthorhombic Li<sub>2</sub>M­(SO<sub>4</sub>)<sub>2</sub> (M = Co, Fe) and their oxidized phases Li<sub><i>x</i></sub>Fe­(SO<sub>4</sub>)<sub>2</sub> (<i>x</i> = 1, 1.5), which were previously studied as potential cathode materials for Li-ion batteries. The particular structure of these orthorhombic compounds (space group <i>Pbca</i>) consists of a three-dimensional network of isolated MO<sub>6</sub> octahedra enabling solely super-super-exchange interactions between transition metals. We studied the magnetic properties of these phases via temperature-dependent susceptibility measurements and applied neutron powder diffraction experiments to solve their magnetic structures. All compounds present an antiferromagnetic long-range ordering of the magnetic spins below their Néel temperature. Their magnetic structures are collinear and follow a spin sequence (+ + – – – – + +), with the time reversal associated with the inversion center, a characteristic necessary for a linear magneto-electric effect. We found that the orientation of the magnetic moments varies with the nature of M. While Li<sub>2</sub>Co­(SO<sub>4</sub>)<sub>2</sub> and Li<sub>1</sub>Fe­(SO<sub>4</sub>)<sub>2</sub> adopt the magnetic space group <i>Pb</i>′<i>c</i>′<i>a</i>′, the magnetic space group for Li<sub>2</sub>Fe­(SO<sub>4</sub>)<sub>2</sub> and Li<sub>1.5</sub>Fe­(SO<sub>4</sub>)<sub>2</sub> is <i>P</i>112<sub>1</sub>′/<i>a</i>, which might hint for a possible monoclinic distortion of their nuclear structure. Moreover we compared the orthorhombic phases to their monoclinic counterparts as well as to the isostructural orthorhombic Li<sub>2</sub>Ni­(SO<sub>4</sub>)<sub>2</sub> compound. Finally, we show that this possible magneto-electric feature is driven by the topology of the magnetic interactions
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