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  • 1.
    Bertrand, Philippe
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Doubaji, Siham
    LCME, University Cadi Ayyad, Marrakech, Morocco.
    Saadoune, Ismael
    LCME, University Cadi Ayyad, Marrakech, Morocco.
    Gorgoi, Mihaela
    Helmholtz Zentrum Berlin.
    Gustafsson, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Solhy, Solhy
    Center for Advanced Materials Université Mohammed VI Polytechnique, Lot 660-Hay Moulay Rachid Ben Guerir, Morocco.
    Valvo, Mario
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Passivation Layer and Cathodic Redox Reactions in Sodium-Ion Batteries Probed by HAXPES  2017Conference paper (Other academic)
    Abstract [en]

    In this presentation, we will present a recent example on electrode/electrolyte interfaces of materials for energy storage devices using hard X-rays photoelectron spectroscopy (HAXPES). A nondestructive analysis was made through the electrode/electrolyte interface of the first electrochemical cycle to ensure access to information not only on the active material, but also on the passivation layer formed at the electrode surface and referred to as the solid permeable interface (SPI). [1]

     

    While electrode/electrolyte study has been performed widely on Li-ion battery, not so much attention as been addressed to the Na-ion technology so far. We will focus in this presentation to NaxCo2/3Mn2/9Ni1/9O2, a novel intercalation material that could be be used as cathode in Na-ion batteries. [2] During a typical charge/discharge cycle (i.e. extraction/insertion of Na+ ions), the oxidation state of the various transition metals in the compound changes in a reversible way. A step by step analysis of the first electrochemical cycle was carried out by HAXPES providing unique information on the oxidation state of Ni, Co and Mn as well as a very interesting insight into the passivation layer present at the surface of the electrode, which results from the degradation of the electrolyte components upon reaction. This investigation shows the role of the SPI and the complexity of the redox reactions. [3]

     

     

    [1] B. Philippe, M. Hahlin, K. Edström, T. Gustafsson, H. Siegbahn, H. Rensmo, J. Electrochem. Soc, 2016, 163, A178-A191

    [2] S. Doubaji, M. Valvo, I. Saadoune, M. Dahbi, K.Edström, J. Power Sources, 2014, 266, 275-281

    [3] S. Doubaji, B. Philippe, I. Saadoune, M. Gorgoi, T. Gustafsson, A. Solhy, M. Valvo, H. Rensmo, K. Edström, ChemSusChem, 2016, 9, 97-108

  • 2.
    Dahbi, Mohammed
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Saadoune, Ismael
    LCME, University Cadi Ayyad, Marrakech, Morocco.
    Gustafsson, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Effect of manganese on the structural and thermal stability of Li 0.3Ni0.7 - yCo0.3−yMn2yO2 electrode materials (y =0 and 0.05)2011In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 203, no 1, p. 37-41Article in journal (Refereed)
    Abstract [en]

    Thermal and structural stabilities of Li(0.3)Ni(0.7)Co(0.3)O(2) and Li(0.3)Ni(0.65)Co(0.25)Mn(0.10)O(2) chemically delithiated cathode materials were studied by X-ray diffraction, thermogravimetric analysis and differential scanning calorimetry. The structure of the Li(0.3)Ni(0.7)Co(0.3)O(2) layered material (S.C. R-3 m) transforms first to the spinel-type structure (S.C. Fd3m) and then to the completely disordered Ni0-type structure (S.C. Fm3m). These structural transitions were accompanied by 10.2% oxygen loss and leads to an exothermic reaction, activated by the electrolyte, more energetic than that of Li(0.3)Ni(0.65)Mn(0.10)O(2) manganese substituted electrode. Furthermore, no structural changes were observed during the thermal treatment of Li(0.3)Ni(0.65)Co(0.25)Mn(0.10)O(2) and relatively lower oxygen loss was recorded. The obtained results prove the positive effect of manganese substitution on the electrochemical features of Li(0.3)Ni(0.7)Co(0.3)O(2).

  • 3.
    Dahbi, Mohammed
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Wikberg, J. Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Saadoune, Ismael
    LCME, FST Marrakech, University Cadi Ayyad, Marocko.
    Gustafsson, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Svedlindh, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Electrochemical behavior of LiNi1-y-zCoyMnzO2 probed through structural and magnetic properties2012In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 111, no 2, p. 023904-Article in journal (Refereed)
    Abstract [en]

    We have investigated LixNi1-y-zCoyMnzO2 compounds with y = 1/3, 0.25, 0.2, 0.1 and z = 1/3, 0.2, 0.1, 0.05 in order to study the influence of Ni and Mn concentration, cationic disorder, and crystallite size on the magnetic and charge/discharge behavior. The samples have been studied by means of x-ray diffraction, scanning electron microscopy, voltammetry, cycling capacity, and magnetometry. The discharge capacity increases with increasing Ni concentration as does the number of ferromagnetic interactions. With higher Mn concentration a higher capacity is observed together with formation of strong antiferromagnetic interactions driving the magnetic frustration to lower temperatures. Our results show that for sufficiently low Co concentrations a stable and magnetically more ordered structure can be obtained with excellent electrochemical properties, although a relatively large amount of Ni is present.

  • 4. Dahbi, Mohammed
    et al.
    Wikberg, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Saadoune, Ismael
    LCME, University Cadi Ayyad, Marrakech, Morocco.
    Gustafsson, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Svedlindh, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    A delithiated LiNi0.65Co0.25Mn0.10O2 electrode material: A structural, magnetic and electrochemical study2009In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 54, no 11, p. 3211-3217Article in journal (Refereed)
    Abstract [en]

    A crystalline LiNi0.65Co0.25Mn0.10O2 electrode material was synthesized by the combustion method at 900 °C for 1 h. Rietveld refinement shows less than 3% of Li/Ni disorder in the structure. Lithium extraction involves only the Ni2+/Ni4+ redox couple while Co3+ and Mn4+ remain electrochemically inactive. No structural transition was detected during cycling in the whole composition range 0 < x < 1.0. Furthermore, the hexagonal cell volume changes by only 3% when all lithium was removed indicating a good mechanical stability of the studied compound. LiNi0.65Co0.25Mn0.10O2 has a discharge capacity of 150 mAh/g in the voltage range 2.5–4.5 V, but the best electrochemical performance was obtained with an upper cut-off potential of 4.3 V. Magnetic measurements reveal competing antiferromagnetic and ferromagnetic interactions – varying in strength as a function of lithium content – yielding a low temperature magnetically frustrated state. The evolution of the magnetic properties with lithium content confirms the preferential oxidation of Ni ions compared to Co3+ and Mn4+ during the delithiation process.

  • 5.
    Difi, Siham
    et al.
    Univ Montpellier, CNRS, Inst Charles Gerhardt, UMR 5253, F-34095 Montpellier 5, France.;Univ Cadi Ayyad, Lab Chim Mat & Environm, Marrakech, Morocco..
    Saadoune, Ismael
    Univ Cadi Ayyad, Lab Chim Mat & Environm, Marrakech, Morocco..
    Sougrati, Moulay Tahar
    Univ Montpellier, CNRS, Inst Charles Gerhardt, UMR 5253, F-34095 Montpellier 5, France.;CNRS, FR 3459, Reseau Stockage Electrochim Energie RS2E, F-80039 Amiens, France..
    Hakkou, Rachid
    Univ Cadi Ayyad, Lab Chim Mat & Environm, Marrakech, Morocco..
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Lippens, Pierre-Emmanuel
    Univ Montpellier, CNRS, Inst Charles Gerhardt, UMR 5253, F-34095 Montpellier 5, France.;CNRS, FR 3459, Reseau Stockage Electrochim Energie RS2E, F-80039 Amiens, France..
    Mechanisms and Performances of Na1.5Fe0.5Ti1.5(PO4)(3)/C Composite as Electrode Material for Na-Ion Batteries2015In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 119, no 45, p. 25220-25234Article in journal (Refereed)
    Abstract [en]

    The properties, insertion mechanisms, and electrochemical performances of the Na1.5Fe0.5Ti1.5(PO4)(3)/C composite as electrode material for Na-ion batteries are reported. The composite was obtained by solid-state reaction and consists of porous secondary particles of submicron-sized particles coated by carbon. Detailed characterizations were performed by combining theoretical and experimental tools. This includes the determination of the crystal structure of Na1.5Fe0.5Ti1.5(PO4)(3) from both first-principles calculations and X-ray diffraction providing Na distribution over M1 and M2 interstitial sites, which is of importance for ionic conductivity. Na1.5Fe0.5Ti1.5(PO4)(3)/C was used as an electrode material at 2.2 V versus Na+/Na-0, exhibiting good Na-storage ability with a specific capacity of 125 mAh g(-1), close to the theoretical value, for the first discharge at C/10, good capacity retention, and Coulombic efficiency of 95% and 99.5% at the 60th cycle, respectively, and high power rate with a decrease of the specific capacity of only 14% from C/10 to 2C. These good performances have been related to the morphology of the composite and substitution of Fe for Ti, leading to an insertion mechanism that differs from that of NaTi2(PO4)(3). This mechanism was quantitatively analyzed from operand Fe-57 Mossbauer spectroscopy used for the first time in both galvanostatic and GITT modes.

  • 6.
    Difi, Siham
    et al.
    Univ Montpellier, CNRS, Inst Charles Gerhardt, UMR 5253, Pl Eugene Bataillon, F-34095 Montpellier 5, France.;Univ Cadi Ayyad, Lab Chim Mat & Environm, Ave A Khattabi,BP 549, Marrakech, Morocco..
    Saadoune, Ismael
    Univ Cadi Ayyad, Lab Chim Mat & Environm, Ave A Khattabi,BP 549, Marrakech, Morocco.;Univ Mohammed VI Polytech, Ctr Adv Mat, Lot 660, Hay Moulay Rachid, Ben Guerir, Morocco..
    Sougrati, Moulay Tahar
    Univ Montpellier, CNRS, Inst Charles Gerhardt, UMR 5253, Pl Eugene Bataillon, F-34095 Montpellier 5, France.;CNRS, Reseau Stockage Electrochim Energie, FR 3459, F-80039 Amiens, France..
    Hakkou, Rachid
    Univ Cadi Ayyad, Lab Chim Mat & Environm, Ave A Khattabi,BP 549, Marrakech, Morocco..
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Lippens, Pierre-Emmanuel
    Univ Montpellier, CNRS, Inst Charles Gerhardt, UMR 5253, Pl Eugene Bataillon, F-34095 Montpellier 5, France.;CNRS, Reseau Stockage Electrochim Energie, FR 3459, F-80039 Amiens, France..
    Role of iron in Na1.5Fe0.5Ti1.5(PO4)(3)/C as electrode material for Na-ion batteries studied by operando Mossbauer spectroscopy2016In: Hyperfine Interactions, 2016, article id 61Conference paper (Refereed)
    Abstract [en]

    The role of iron in Na1.5Fe0.5Ti1.5(PO4)(3)/C electrode material for Na batteries has been studied by Fe-57 Mossbauer spectroscopy in operando mode. The potential profile obtained in the galvanostatic regime shows three plateaus at different voltages due to different reaction mechanisms. Two of them, at 2.2 and 0.3 V vs Na+/Na-0, have been associated to redox processes involving iron and titanium in Na1.5Fe0.5Ti1.5(PO4)(3). The role of titanium was previously elucidated for NaTi2(PO4)(3) and the effect of the substitution of Fe for Ti was investigated with 57Fe Mossbauer spectroscopy. We show that iron is an electrochemically active center at 2.2 V with the reversible Fe3+/Fe2+ transformation and then remains at the oxidation state Fe2+ along the sodiation until the end of discharge at 0 V.

  • 7.
    Doubaji, Siham
    et al.
    LCME, University Cadi Ayyad, Marrakech, Morocco.
    Ma, Lu
    Argonne Naional Laboratory.
    Asfaw, Habtom Desta
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Izanzar, Ilyasse
    LCME, University Cadi Ayyad, Marrakech, Morocco.
    Xu, Rui
    Argonne National Laboratory.
    Alami, Jones
    Mohammed VI Polytechnic University (UM6P), Ben Guerir, Morocco.
    Lu, Jun
    Argonne National Laboratory.
    Wu, Tianpin
    Argonne National Laboratory.
    Amine, Khalil
    Argonne National Laboratory.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Saadoune, Ismael
    LCME, University Cadi Ayyad, Marrakech, Morocco.; Mohammed VI Polytech Univ UM6P, Mat Sci & Nanoengn Dept, Lot 660 Hay My Rachid, Ben Guerir 43150, Morocco..
    On the P2-NaxCo1−y(Mn2/3Ni1/3)yO2 Cathode Materials for Sodium-Ion Batteries: Synthesis, Electrochemical Performance, and Redox Processes Occurring during the Electrochemical Cycling2018In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, no 1, p. 488-501Article in journal (Refereed)
    Abstract [en]

    P2-type NaMO2sodiated layered oxides withmixed transition metals are receiving considerable attention foruse as cathodes in sodium-ion batteries. A study on solidsolution (1−y)P2-NaxCoO2−(y)P2-NaxMn2/3Ni1/3O2(y=0,1/3, 1/2, 2/3, 1) reveals that changing the composition of thetransition metals affects the resulting structure and the stabilityof pure P2 phases at various temperatures of calcination. For 0≤y≤1.0, the P2-NaxCo(1−y)Mn2y/3Niy/3O2solid-solutioncompounds deliver good electrochemical performance whencycled between 2.0 and 4.2 V versus Na+/Na with improved capacity stability in long-term cycling, especially for electrodematerials with lower Co content (y= 1/2 and 2/3), despite lower discharge capacities being observed. The (1/2)P2-NaxCoO2−(1/2)P2-NaxMn2/3Ni1/3O2composition delivers a discharge capacity of 101.04 mAh g−1with a capacity loss of only 3% after 100cycles and a Coulombic efficiency exceeding 99.2%. Cycling this material to a higher cutoffvoltage of 4.5 V versus Na+/Naincreases the specific discharge capacity to≈140 mAh g−1due to the appearance of a well-defined high-voltage plateau, but afteronly 20 cycles, capacity retention declines to 88% and Coulombic efficiency drops to around 97%. In situ X-ray absorption near-edge structure measurements conducted on composition NaxCo1/2Mn1/3Ni1/6O2(y= 1/2) in the two potential windows studiedhelp elucidate the operating potential of each transition metal redox couple. It also reveals that at the high-voltage plateau, all ofthe transition metals are stable, raising the suspicion of possible contribution of oxygen ions in the high-voltage plateau.

  • 8.
    Doubaji, Siham
    et al.
    Univ Cadi Ayyad, FST Marrakesh, LCME, Marrakech 40000, Morocco..
    Philippe, Bertrand
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Saadoune, Ismael
    Univ Cadi Ayyad, FST Marrakesh, LCME, Marrakech 40000, Morocco.;Univ Mohammed VI Polytech, Ctr Adv Mat, Ben Guerir, Morocco..
    Gorgoi, Mihaela
    Helmholtz Zentrum Berlin Mat & Energie, D-12489 Berlin, Germany..
    Gustafsson, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Solhy, Abderrahim
    Univ Mohammed VI Polytech, Ctr Adv Mat, Ben Guerir, Morocco..
    Valvo, Mario
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Passivation Layer and Cathodic Redox Reactions in Sodium-Ion Batteries Probed by HAXPES2016In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 9, no 1, p. 97-108Article in journal (Refereed)
    Abstract [en]

    The cathode material P2-NaxCo2/3Mn2/9Ni1/9O2, which could be used in Na-ion batteries, was investigated through synchrotron-based hard X-ray photoelectron spectroscopy (HAXPES). Nondestructive analysis was made through the electrode/electrolyte interface of the first electrochemical cycle to ensure access to information not only on the active material, but also on the passivation layer formed at the electrode surface and referred to as the solid permeable interface (SPI). This investigation clearly shows the role of the SPI and the complexity of the redox reactions. Cobalt, nickel, and manganese are all electrochemically active upon cycling between 4.5 and 2.0V; all are in the 4+ state at the end of charging. Reduction to Co3+, Ni3+, and Mn3+ occurs upon discharging and, at low potential, there is partial reversible reduction to Co2+ and Ni2+. A thin layer of Na2CO3 and NaF covers the pristine electrode and reversible dissolution/reformation of these compounds is observed during the first cycle. The salt degradation products in the SPI show a dependence on potential. Phosphates mainly form at the end of the charging cycle (4.5V), whereas fluorophosphates are produced at the end of discharging (2.0V).

  • 9.
    Doubaji, Siham
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry. LCME, University Cadi Ayyad, Marrakech, Morocco.
    Valvo, Mario
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Saadoune, Ismael
    LCME, University Cadi Ayyad, Marrakech, Morocco.
    Dahbi, Mohammed
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Synthesis and characterization of a new layered cathode material for sodium ion batteries2014In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 266, p. 275-281Article in journal (Refereed)
    Abstract [en]

    Owing to the high abundance of sodium and its low cost compared to lithium, sodium ion batteries have recently attracted a renewed interest as possible candidates for stationary and mobile energy storage devices. Herein, we present a new sodium ion intercalation material, Na5CO2/3Mn2/9Ni1/9O2, which has been synthesized by a sol gel route in air followed by a heat treatment at 800 degrees C for 12 h. Its structure has been studied by X-ray diffraction showing that the material crystallized in a P2-type structure (space group P6(3)/mmc). As far as the electrochemical properties of NaxCo2/3Mn2/9Ni1/9O2 as positive electrode are concerned, this compound offers a specific capacity of 110 mAh g(-1) when cycled between 2.0 and 4.2 V vs. Na+/Na. The electrodes exhibited a good capacity retention and a coulombic efficiency exceeding 99.4%, as well as a reversible discharge capacity of 140 mAh g(-1) when cycled between 2.0 and 4.5 V. These results represent a further step towards the realization of efficient sodium ion batteries, especially considering that the synthesis method proposed here is simple and cost effective and that all the electrochemical measurements were carried out without any use of additives or any optimization for both the materials and the cell components. 

  • 10.
    Eriksson, Rickard
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Lasri, Karima
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Gorgoi, Mihaela
    Helmholtz Zentrum Berlin.
    Gustafsson, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Brandell, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Saadoune, Ismael
    LCME, University Cadi Ayyad, Marrakech, Morocco.
    Hahlin, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Electronic and Structural Changes in Ni0.5TiOPO4 Li-ion Battery Cells Upon First Lithiation and Delithiation, Studied by High-Energy X-ray Spectroscopies2015In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 119, no 18, p. 9692-9704Article in journal (Refereed)
  • 11.
    Eriksson, Rickard
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Maher, Kenza
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Saadoune, Ismael
    LCME, University Cadi Ayyad, Marrakech, Morocco.
    Mansori, Mohammed
    LCME, University Cadi Ayyad, Marrakech, Morocco.
    Gustafsson, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Electrochemical lithium ion intercalation in Li 0.5Ni 0.25TiOPO 4 examined by in situ X-ray diffraction2012In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 225, no SI, p. 547-550Article in journal (Refereed)
    Abstract [en]

    The complex structural transformations of Li 0.5Ni 0.25TiOPO 4 during electrochemical lithiation have been examined by in situ X-ray diffraction. During the first lithiation two structural changes take place: first a transition to a second monoclinic phase (a = 9.085(4), b = 8.414(5), c = 6.886(5), β = 99.85(4)) and secondly a transition to a third phase with limited long-range order. The third phase is held together by a network of corner sharing Ti-O octahedra and phosphate ions with disordered Ni-Li channels. During delithiation the third phase is partially transformed back to a slightly disordered original phase, Li 0.5Ni 0.25TiOPO 4 without formation of the second intermediate phase. These phase transitions correspond well to the different voltage plateaus that this material shows during electrochemical cycling.

  • 12.
    Hollmark, H.M.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Duda, Laurent-Claudius
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Dahbi, Mohammed
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Saadoune, Ismael
    LCME, University Cadi Ayyad, Marrakech, Morocco.
    Gustafsson, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Resonant Soft X-Ray Emission Spectroscopy and X-Ray Absorption Spectroscopy on the Cathode Material LiNi0.65Co0.25Mn0.1O22010In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 157, no 8, p. A962-A966Article in journal (Refereed)
  • 13.
    Hollmark, H.M.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Maher, K.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Saadoune, Ismael
    LCME, University Cadi Ayyad, Marrakech, Morocco.
    Gustafsson, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Duda, Laurent-Claudius
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Resonant inelastic X-ray scattering and X-ray absorption spectroscopy on the negative electrode material Li0.5Ni0.25TiOPO4 in a Li-ion battery2011In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 13, no 14, p. 6544-6551Article in journal (Refereed)
  • 14.
    Hollmark, Håkan M.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Duda, Laurent
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Dahbi, Mohammed
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Saadoune, Ismael
    LCME, University Cadi Ayyad, Marrakech, Morocco.
    Gustafsson, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Resonant Soft X-Ray Emission Spectroscopy and X-Ray Absorption Spectroscopy on the Cathode Material LiNi0.65Co0.25Mn0.1O22010In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 157, no 8, p. A962-A966Article in journal (Refereed)
    Abstract [en]

    We present a study of the charge-state behavior of the Li-ion battery cathode material LixNi(0.65)Co(0.25)Mn(0.1)O(2) as observed by X-ray absorption spectroscopy (XAS) and resonant soft X-ray emission (RSXE). A set of six identical Li//LixNi0.65Co0.25Mn0.1O2 batteries has been cycled and is studied in different states of charge in the range of x = 1.0, ... ,0.2 before disassembly in an Ar glove box. Site and symmetry selective information about the electronic structure of the conduction and valence bands reveals that Ni as well as Co ions participate in the uptake and release of the extra electron charge that the inserted Li ions provide, but the Ni ion is much less than expected. The net amount of charge on the oxygen varies approximately 0.24 charge units in the range of x, and dramatic changes in the hybridization are evident in XAS and in particular in RSXE at the O K edge. We attribute this to a strong screening behavior of the Li ions between the oxide layers. Structural integrity effects limit the extraction of Li ions to a value of about x = 0.2-0.4. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3454739] All rights reserved.

  • 15.
    Hollmark, Håkan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Maher, Kenza
    ECME, FST Marrakech, University Cadi Ayyad, BP549, Av. A. Khattabi, Marrakech, Morocco.
    Saadoune, Ismael
    ECME, FST Marrakech, University Cadi Ayyad, BP549, Av. A. Khattabi, Marrakech, Morocco.
    Gustafsson, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Duda, Laurent-C.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Soft X-Ray Physics.
    Resonant inelastic X-ray scattering and X-ray absorption spectroscopy on the negative electrode material Li0.5Ni0.25TiOPO4 in a Li-ion battery2011In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 13, no 14, p. 6544-6551Article in journal (Refereed)
    Abstract [en]

    We have studied the first lithiation/delithiation cycle of the Li-ion battery electrode material LixNi0.25TiOPO4 applying X-ray absorption spectroscopy (XAS) and resonant inelastic X-ray scattering (RIXS). A set of ten identical LixNi0.25TiOPO4 battery electrodes have been cycled and left in different states of charge in the range of x = 0.5 … 2.5, before disassembly in an Ar filled glove box. We find that Ni-, Ti-, and O-ions are affected simultaneously, rather than sequentially, upon lithiation of the material. In particular, Ni is reduced from Ni2+ to Ni0 but only partially re-oxidized to Ni1+, again, by delithiation. Overall, there is considerable “crosstalk” between the different atomic species and non-linearity in the response of the electronic structure during the lithiation/delithiation process. Fortuitously, the background variation in Ni L-XAS shows to contain valuable information about solid–electrolyte interface (SEI) creation, showing that the SEI is a function of the degree of lithiation.

  • 16.
    Lasri, Karima
    et al.
    Univ Cadi Ayyad, FST Marrakech, LCME, Ave A Khattabi,BP 549, Marrakech 40000, Morocco..
    Brandell, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Saadoune, Ismael
    Univ Cadi Ayyad, FST Marrakech, LCME, Ave A Khattabi,BP 549, Marrakech 40000, Morocco.;Univ Mohammed VI Polytech, Ctr Adv Mat, Lot 660 Hay Moulay Rachid, Ben Guerir, Morocco..
    Larzek, Mohamed
    Univ Mohammed VI Polytech, Ctr Adv Mat, Lot 660 Hay Moulay Rachid, Ben Guerir, Morocco..
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Electrochemical characterizations of Co0.5TiOPO4 as anode material for lithium-ion batteries2016In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 148, p. 44-51Article in journal (Refereed)
    Abstract [en]

    Titanium oxyphosphate M0.5TiOPO4 (M=Ni, Cu, Fe) represent a promising candidate as an anode material for the lithium-ion batteries thanks to their good energetic performance and structural stability. In this work, we report on the high capacity of Co0.5TiOPO4/C electrode material. In particular, at C rate, the discharge capacity of more than 210 mA h/g was maintained for 80 charge/discharge cycles. Furthermore, Co0.5TiOPO4/C composite exhibits excellent rate-capability with excellent coulombic efficiency. The outstanding electrochemical performance of Co0.5TiOPO4/C anode material might be attributed to its well crystallinity, controlled morphology due to the sol-gel preparation method, and the particles surface carbon-coating.

  • 17.
    Lasri, Karima
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Saadoune, Ismael
    LCME, University Cadi Ayyad, Marrakech, Morocco.
    Bentaleb, Yassine
    Mikhailova, Daria
    Ehrenberg, Helmut
    Häggström, Lennart
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Origin of the irreversible capacity of the Fe0.5TiOPO4 anode material2012In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 224, p. 15-20Article in journal (Refereed)
    Abstract [en]

    Fe0.5TiOPO4 oxyphosphate was prepared directly by solid state reaction. It crystallizes in the monoclinic system with P2(1)/c space group and the use of Fe0.5TiOPO4 as an active material in lithium-ion batteries shows two potential plateaus and an irreversible discharge capacity of similar to 200 rnAh/g. To understand the origin of this irreversibility, a series of LixFe0.5TiOPO4 (x = 0.06, 0.21 0.76, 1.14) were chemically prepared and analyzed by X-ray diffraction. A structure amorphization of the LixFe0.5TiOPO4 phosphates takes place during the lithiation process. Magnetization and Mossbauer spectroscopy studies of the LixFe0.5TiOPO4 samples clearly show the formation of iron metal which induces a deterioration of the crystal structure of the studied electrode materials. The lithiation process leads thus to a conversion reaction which explains the irreversibility of the electrochemical process during the first discharge. (C) 2012 Elsevier B.V. All rights reserved.

  • 18.
    Lasri, Karime
    et al.
    LCME, University Cadi Ayyad, Marrakech, Morocco.
    Dahbi, Mohammed
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Liivat, Anti
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Brandell, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Saadoune, Ismael
    LCME, University Cadi Ayyad, Marrakech, Morocco.
    Intercalation and conversion reactions in Ni0.5TiOPO4 Li-ion battery anode materials2013In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 229, p. 265-271Article in journal (Refereed)
    Abstract [en]

    The Ni0.5TiOPO4/C composite Li-ion battery anode material has been prepared by a sol-gel method with a subsequent pyrolysis step for the formation of C-coating. The resulting sub-micronsized particles displayed a narrow particle size distribution and a corresponding high electrochemical activity which, in turn, facilitates in-depth analysis of the electrochemical behavior of the material. It is shown that by limiting the degree of lithiation in the material, the redox potential in subsequent cycles is substantially affected. Ex-situ XRD reveals a gradual evolution of the structure during cycling of the material, with lower crystallinity after the first discharge cycle. By correlating the electrochemical properties with the structural studies, new insights into the electrochemical behavior of the Ni0.5TiOPO4/C anode material are achieved, suggesting a combination of intercalation and conversion reactions.

  • 19.
    Maher, Kenza
    et al.
    LCME, University Cadi Ayyad, Marrakech, Morocco.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Saadoune, Ismael
    LCME, University Cadi Ayyad, Marrakech, Morocco.
    Gustafsson, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Mansori, Mohammed
    LCME, University Cadi Ayyad, Marrakech, Morocco.
    The electrochemical behaviour of the carbon-coated Ni0.5TiOPO4 electrode material2011In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 196, no 5, p. 2819-2825Article in journal (Refereed)
    Abstract [en]

    Ni0.5TiOPO4 oxyphosphate exhibits good electrochemical properties as an anode material in lithium ion batteries but suffers from its low conductivity. We present here the electrochemical performances of the synthesized Ni0.5TiOPO4/carbon composite by using sucrose as the carbon source. X-ray diffraction study confirms that this phosphate crystallizes in the monoclinic system (S.G. P21/c). The use of the Ni0.5TiOPO4/C composite in lithium batteries shows enhanced electrochemical performances compared with the uncoated material. Capacities up to 200 mAh g−1 could be reached during cycling of this electrode. Furthermore, an acceptable rate capability was obtained with very low capacity fading even at 0.5C rate. Nevertheless, a considerable irreversible capacity was evidenced during the first discharge. In situ synchrotron X-ray radiation was utilized to study the structural change during the first discharge in order to evidence the origin of this irreversible capacity. Lithium insertion during the first discharge induces an amorphization of the crystal structure of the parent material accompanied by an irreversible formation of a new phase.

  • 20.
    Saadoune, Ismael
    et al.
    LCME, University Cadi Ayyad, Marrakech, Morocco.
    Dahbi, Mohammed
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Wikberg, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Gustafsson, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Svedlindh, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Effect of the synthesis temperature on the structure and electrochemical behaviour of the LiNi0.65Co0.25Mn0.1O2 positive electrode material2008In: Solid State Ionics, ISSN 0167-2738, E-ISSN 1872-7689, Vol. 178, no 31-32, p. 1668-1675Article in journal (Refereed)
    Abstract [en]

    Three kinds of LiNi0.65Co0.25Mn0.1O2 samples were prepared using a combustion method at different synthetic conditions (C1: 900 °C/1 h; C2: 900 °C/12 h and C3: 1000 °C/12 h). The samples were characterized using X-ray diffraction, scanning electron microscopy and magnetization measurements before their use as positive electrode material in lithium-ion batteries. Sample C1 presents the most ordered structure with less than 3% of nickel ions in the lithium plane. Increasing synthesis temperature and/or time lead to an increase of the Li/Ni disorder. The amount of extra-nickel ions in the lithium plane strongly affects the magnetic behaviour and the electrochemical performances of the prepared material. LiNi0.65Co0.25Mn0.1O2 prepared at 900 °C for 1 h presents the best cycling properties.

  • 21.
    Wikberg, J. Magnus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Dahbi, Mohammed
    ECME, LP2E2M, FST Marrakech, University Cadi Ayyad.
    Saadoune, Ismael
    ECME, LP2E2M, FST Marrakech, University Cadi Ayyad.
    Gustafsson, Torbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Edström, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Svedlindh, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Magnetic order, aging, and spin frustration in a percolating spin system, LiNi0.8Co0.1Mn0.1O22010In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 108, no 8, p. 083909-Article in journal (Refereed)
    Abstract [en]

    Structural and magnetic properties of the Li layered oxide, LiNi0.8Co0.1Mn0.1O2, have been studied by means of x-ray diffraction, dc magnetization, ac linear, and nonlinear susceptibility as well as by magnetic aging and temperature cycling experiments. A percolating spin system interacting via antiferromagnetic and ferromagnetic superexchange interactions of different strength induce a ferrimagnetic quasilong-range order with a transition temperature Tc ≈ 70 K, a Weiss temperature of −25 K and an effective magnetic moment of 2.07 μB. On cooling below Tc the two-dimensional (2D) triangular lattice built up of edge-sharing metal oxide octahedras first exhibits a 2D spin glass like behavior followed by complete spin frustration in three dimensions below 30 K. The findings correlate well with expectations for a ferrimagnetic reentrant cluster glass system as well as with predictions of the percolating cluster model.

1 - 21 of 21
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