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Author Forsh, E.A.; Abakumov, A.M.; Zaytsev, V.B.; Konstantinova, E.A.; Forsh, P.A.; Rumyantseva, M.N.; Gaskov, A.M.; Kashkarov, P.K.
  Title Optical and photoelectrical properties of nanocrystalline indium oxide with small grains Type A1 Journal article
  Year 2015 Publication Thin solid films : an international journal on the science and technology of thin and thick films Abbreviated Journal Thin Solid Films
  Volume 595 Issue 595 Pages 25-31
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract Optical properties, spectral dependence of photoconductivity and photoconductivity decay in nanocrystalline indium oxide In2O3 are studied. A number of nanostructured In2O3 samples with various nanocrystals size are prepared by sol-gel method and characterized using various techniques. The mean nanocrystals size varies from 7 to 8 nm to 39-41 nm depending on the preparation conditions. Structural characterization of the In2O3 samples is performed by means of transmission electron microscopy and X-ray powder diffraction. The combined analysis of ultraviolet-visible absorption spectroscopy and diffuse reflectance spectroscopy shows that nanostructuring leads to the change in optical band gap: optical band gap of the In2O3 samples (with an average nanocrystal size from 7 to 41 nm) is equal to 2.8 eV. We find out the correlation between spectral dependence of photoconductivity and optical properties of nanocrystalline In2O3: sharp increase in photoconductivity was observed to begin at 2.8 eV that is equal to the optical bandgap in the In2O3 samples, and reached its maximum at 3.2-3.3 eV. The combined analysis of the slow photoconductivity decay in air, vacuum and argon, that was accurately fitted by a stretched-exponential function, and electron paramagnetic resonance (EPR) measurements shows that the kinetics of photoconductivity decay is strongly depended on the presence of oxygen molecules in the ambient of In2O3 nanocrystals. There is the quantitative correlation between EPR and photoconductivity data. Based on the obtained data we propose the model clearing up the phenomenon of permanent photoconductivity decay in nanocrystalline In2O3. (C) 2015 Elsevier B.V. All rights reserved.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Lausanne Editor
  Language Wos 000365812400005 Publication Date 2015-10-27
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0040-6090 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 1.879 Times cited 18 Open Access (down)
  Notes Approved Most recent IF: 1.879; 2015 IF: 1.759
  Call Number UA @ lucian @ c:irua:130254 Serial 4219
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Author Ryabova, A.S.; Napolskiy, F.S.; Poux, T.; Istomin, S.Y.; Bonnefont, A.; Antipin, D.M.; Baranchikov, A.Y.; Levin, E.E.; Abakumov, A.M.; Kéranguéven, G.; Antipov, E.V.; Tsirlina, G.A.; Savinova, E.R.;
  Title Rationalizing the influence of the Mn(IV)/Mn(III) red-Ox transition on the electrocatalytic activity of manganese oxides in the oxygen reduction reaction Type A1 Journal article
  Year 2016 Publication Electrochimica acta Abbreviated Journal Electrochim Acta
  Volume 187 Issue 187 Pages 161-172
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract Knowledge on the mechanisms of oxygen reduction reaction (ORR) and descriptors linking the catalytic activity to the structural and electronic properties of transition metal oxides enable rational design of more efficient catalysts. In this work ORR electrocatalysis was studied on a set of single and complex Mn (III) oxides with a rotating disc electrode method and cyclic voltammetry. We discovered an exponential increase of the specific electrocatalytic activity with the potential of the surface Mn(IV)/Mn(III) red-ox couple, suggesting the latter as a new descriptor for the ORR electrocatalysis. The observed dependence is rationalized using a simple mean-field kinetic model considering availability of the Mn( III) centers and adsorbate-adsorbate interactions. We demonstrate an unprecedented activity of Mn2O3, ca. 40 times exceeding that of MnOOH and correlate the catalytic activity of Mn oxides to their crystal structure. (C) 2015 Elsevier Ltd. All rights reserved.
  Address
  Corporate Author Thesis
  Publisher Place of Publication London Editor
  Language Wos 000367235600019 Publication Date 2015-11-10
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0013-4686 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 4.798 Times cited 51 Open Access (down)
  Notes Approved Most recent IF: 4.798
  Call Number UA @ lucian @ c:irua:131096 Serial 4237
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Author Charkin, D.O.; Akinfiev, V.S.; Alekseeva, A.M.; Batuk, M.; Abakumov, A.M.; Kazakov, S.M.
  Title Synthesis and cation distribution in the new bismuth oxyhalides with the Sillen-Aurivillius intergrowth structures Type A1 Journal article
  Year 2015 Publication Journal of the Chemical Society : Dalton transactions Abbreviated Journal Dalton T
  Volume 44 Issue 44 Pages 20568-20576
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract About 20 new compounds with the Sillen-Aurivillius intergrowth structure, (MeMeBi3Nb2O11X)-Me-1-Bi-2 (Me-1 = Pb, Sr, Ba; Me-2 = Ca, Sr, Ba; X = Cl, Br, I), have been prepared. They are composed of stacking of [ANb(2)O(7)] perovskite blocks, fluorite-type [M2O2] blocks and halogen sheets. The cation distribution between the fluorite and perovskite layers has been studied for Ba2Bi3Nb2O11I, Ca1.25Sr0.75Bi3Nb2O11Cl, BaCaBi3Nb2O11Br and Sr2Bi3Nb2O11Cl. The smaller Me cations tend to reside in the perovskite block while the larger ones are situated in the fluorite-type block. The distribution of the elements was confirmed for BaCaBi3Nb2O11Br using energy dispersive X-ray analysis combined with scanning transmission electron microscopy (STEM-EDX). An electron diffraction study of this compound reveals a local symmetry lowering caused by weakly correlated rotation of NbO6 octahedra. Based on our findings, we suggest a new stability criterion for mixed-layer structures, which is that net charges of any two consecutive layers do not compensate for each other and only the whole layer sequence is electroneutral.
  Address
  Corporate Author Thesis
  Publisher Place of Publication London Editor
  Language Wos 000365411500036 Publication Date 2015-10-30
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0300-9246; 1477-9226; 1472-7773 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 4.029 Times cited 5 Open Access (down)
  Notes Approved Most recent IF: NA
  Call Number UA @ lucian @ c:irua:130330 Serial 4256
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Author Rozova, M.G.; Grigoriev, V.V.; Bobrikov, I.A.; Filimonov, D.S.; Zakharov, K.V.; Volkova, O.S.; Vasiliev, A.N.; Antipov, E.V.; Tsirlin, A.A.; Abakumov, A.M.
  Title Synthesis, structure and magnetic ordering of the mullite-type Bi2Fe4-xCrxO9 solid solutions with a frustrated pentagonal Cairo lattice Type A1 Journal article
  Year 2016 Publication Journal of the Chemical Society : Dalton transactions Abbreviated Journal Dalton T
  Volume 45 Issue 45 Pages 1192-1200
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract Highly homogeneous mullite-type solid solutions Bi2Fe4-xCrxO9 (x = 0.5, 1, 1.2) were synthesized using a soft chemistry technique followed by a solid-state reaction in Ar. The crystal structure of Bi2Fe3CrO9 was investigated using X-ray and neutron powder diffraction, transmission electron microscopy and Fe-57 Mossbauer spectroscopy (S.G. Pbam, a = 7.95579(9) angstrom , b = 8.39145(9) angstrom, c = 5.98242(7) angstrom, R-F(X-ray) = 0.022, R-F(neutron) = 0.057). The ab planes in the structure are tessellated with distorted pentagonal loops built up by three tetrahedrally coordinated Fe sites and two octahedrally coordinated Fe/Cr sites, linked together in the ab plane by corner-sharing forming a pentagonal Cairo lattice. Magnetic susceptibility measurements and powder neutron diffraction show that the compounds order antiferromagnetically (AFM) with the Neel temperatures decreasing upon increasing the Cr content from T-N similar to 250 K for x = 0 to T-N similar to 155 K for x = 1.2. The magnetic structure of Bi2Fe3CrO9 at T = 30 K is characterized by a propagation vector k = (1/2,1/2,1/2). The tetrahedrally coordinated Fe cations form singlet pairs within dimers of corner-sharing tetrahedra, but spins on the neighboring dimers are nearly orthogonal. The octahedrally coordinated (Fe, Cr) cations form antiferromagnetic up-up-down-down chains along c, while the spin arrangement in the ab plane is nearly orthogonal between nearest neighbors and collinear between second neighbors. The resulting magnetic structure is remarkably different from the one in pure Bi2Fe4O9 and features several types of spin correlations even on crystallographically equivalent exchange that may be caused by the simultaneous presence of Fe and Cr on the octahedral site.
  Address
  Corporate Author Thesis
  Publisher Place of Publication London Editor
  Language Wos 000367614700041 Publication Date 2015-11-30
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0300-9246; 1477-9226; 1472-7773 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 4.029 Times cited Open Access (down)
  Notes Approved Most recent IF: NA
  Call Number UA @ lucian @ c:irua:131095 Serial 4257
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Author Retuerto, M.; Skiadopoulou, S.; Li, M.R.; Abakumov, A.M.; Croft, M.; Ignatov, A.; Sarkar, T.; Abbett, B.M.; Pokorný, J.; Savinov, M.; Nuzhnyy, D.; Prokleška, J.; Abeykoon, M.; Stephens, P.W.; Hodges, J.P.; Vaněk, P.; Fennie, C.J.; Rabe, K.M.; Kamba, S.; Greenblatt, M.;
  Title Pb2MnTeO6 double perovskite : an antipolar anti-ferromagnet Type A1 Journal article
  Year 2016 Publication Inorganic chemistry Abbreviated Journal Inorg Chem
  Volume 55 Issue 55 Pages 4320-4329
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract Pb2MnTeO6, a new double perovskite, was synthesized. Its crystal structure was determined by synchrotron X-ray and powder neutron diffraction. Pb2MnTeO6 is monoclinic (I2/m) at room temperature with a regular arrangement of all the cations in their polyhedra. However, when the temperature is lowered to similar to 120 K it undergoes a phase transition from I2/m to C2/c structure. This transition is accompanied by a displacement of the Pb atoms from the center of their polyhedra due to the 6s2 lone-pair electrons, together with a surprising off-centering of Mn2+ (d5) magnetic cations. This strong first-order phase transition is also evidenced by specific heat, dielectric, Raman, and infrared spectroscopy measurements. The magnetic characterizations indicate an anti-ferromagnetic (AFM) order below TN approximate to 20 K; analysis of powder neutron diffraction data confirms the magnetic structure with propagation vector k = (0 1 0) and collinear AFM spins. The observed jump in dielectric permittivity near similar to 150 K implies possible anti-ferroelectric behavior; however, the absence of switching suggests that Pb2MnTeO6 can only be antipolar. First-principle calculations confirmed that the crystal and magnetic structures determined are locally stable and that anti-ferroelectric switching is unlikely to be observed in Pb2MnTeO6.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Easton, Pa Editor
  Language Wos 000375519700027 Publication Date 2016-04-08
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0020-1669 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 4.857 Times cited 9 Open Access (down)
  Notes Approved Most recent IF: 4.857
  Call Number UA @ lucian @ c:irua:134219 Serial 4258
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Author Mikita, R.; Aharen, T.; Yamamoto, T.; Takeiri, F.; Ya, T.; Yoshimune, W.; Fujita, K.; Yoshida, S.; Tanaka, K.; Batuk, D.; Abakumov, A.M.; Brown, C.M.; Kobayashi, Y.; Kageyama, H.;
  Title Topochemical nitridation with anion vacancy -assisted N3-/O2- exchange Type A1 Journal article
  Year 2016 Publication Journal of the American Chemical Society Abbreviated Journal J Am Chem Soc
  Volume 138 Issue 138 Pages 3211-3217
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract We present how the introduction of anion vacancies in oxyhydrides enables a route to access new oxynitrides, by conducting ammonolysis of perovskite oxyhydride EuTiO3-xHx (x similar to 0.18). At 400 degrees C, similar to our studies on BaTiO3-xHx, hydride lability enables a low temperature direct ammonolysis of EUTi3.82+O-2.82/H-0.18, leading to the N3-/H--exchanged product EuTi4+O2.82No0.12 square 0.06 center dot When the ammonolysis temperature was increased up to 800 degrees C, we observed a further nitridation involving N3-/O2- exchange, yielding a fully oxidized Eu3+Ti4+O2N with the GdFeO3-type distortion (Pnma) as a metastable phase, instead of pyrochlore structure. Interestingly, the same reactions using the oxide EuTiO3 proceeded through a 1:1 exchange of N3- with O-2 only above 600 degrees C and resulted in incomplete nitridation to EuTi02.25N0.75, indicating that anion vacancies created during the initial nitridation process of EuTiO2.82H0.18 play a crucial role in promoting anion (N3-/O2-) exchange at high temperatures. Hence, by using (hydride-induced) anion-deficient precursors, we should be able to expand the accessible anion composition of perovskite oxynitrides.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Washington, D.C. Editor
  Language Wos 000371945800055 Publication Date 2016-02-08
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0002-7863 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 13.858 Times cited 28 Open Access (down)
  Notes Approved Most recent IF: 13.858
  Call Number UA @ lucian @ c:irua:133156 Serial 4266
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Author Ryabova, A.S.; Bonnefont, A.; Zagrebin, P.; Poux, T.; Sena, R.P.; Hadermann, J.; Abakumov, A.M.; Kerangueven, G.; Istomin, S.Y.; Antipov, E.V.; Tsirlina, G.A.; Savinova, E.R.
  Title Study of hydrogen peroxide reactions on manganese oxides as a tool to decode the oxygen reduction reaction mechanism Type A1 Journal article
  Year 2016 Publication ChemElectroChem Abbreviated Journal Chemelectrochem
  Volume 3 Issue 3 Pages 1667-1677
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract Hydrogen peroxide has been detected as a reaction intermediate in the electrochemical oxygen reduction reaction (ORR) on transition-metal oxides and other electrode materials. In this work, we studied the electrocatalytic and catalytic reactions of hydrogen peroxide on a set of Mn oxides, Mn2O3, MnOOH, LaMnO3, MnO2, and Mn3O4, that adopt different crystal structures to shed light on the mechanism of the ORR on these materials. We then combined experiment with kinetic modeling with the objective to correlate the differences in the ORR activity to the kinetics of the elementary reaction steps, and we uncovered the importance of structural and compositional factors in the catalytic activity of the Mn oxides. We concluded that the exceptional activity of Mn2O3 in the ORR is due to its high catalytic activity both in the reduction of oxygen to hydrogen peroxide and in the decomposition of the latter, and furthermore, we proposed a tentative link between crystal structure and reactivity.
  Address
  Corporate Author Thesis
  Publisher Wiley Place of Publication Place of publication unknown Editor
  Language Wos 000388377200019 Publication Date 2016-07-14
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 2196-0216 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 4.136 Times cited 20 Open Access (down)
  Notes Approved Most recent IF: 4.136
  Call Number UA @ lucian @ c:irua:139202 Serial 4449
Permanent link to this record
 

 
Author Kuno, Y.; Tassel, C.; Fujita, K.; Batuk, D.; Abakumov, A.M.; Shitara, K.; Kuwabara, A.; Moriwake, H.; Watabe, D.; Ritter, C.; Brown, C.M.; Yamamoto, T.; Takeiri, F.; Abe, R.; Kobayashi, Y.; Tanaka, K.; Kageyama, H.
  Title ZnTaO2N: Stabilized High-Temperature LiNbO3-type Structure Type A1 Journal article
  Year 2016 Publication Journal of the American Chemical Society Abbreviated Journal J Am Chem Soc
  Volume 138 Issue 138 Pages 15950-15955
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract By using a high-pressure reaction, we prepared a new oxynitride ZnTaO2N that crystallizes in a centrosymmetric (R (3) over barc) high-temperature LiNbO3-type structure (HTLN-type). The stabilization of the HTLN-type structure down to low temperatures (at least 20 K) makes it possible to investigate not only the stability of this phase, but also the phase transition to a noncentrosymmetric (R3c) LiNbO3-type structure (LN-type) which is yet to be clarified. Synchrotron and neutron diffraction studies in combination with transmission electron microscopy show that Zn is located at a disordered 12c site instead of 6a, implying an order disorder mechanism of the phase transition. It is found that the dosed d-shell of Zn2+, as well as the high-valent Ta5+ ion, is responsible for the stabilization of the HTLN-type structure, affording a novel quasitriangular ZnO2N coordination. Interestingly, only 3% Zn substitution for MnTaO2N induces a phase transition from LN- to HTLN-type structure, implying the proximity in energy between the two structural types, which is supported by the first-principles calculations.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Washington, D.C. Editor
  Language Wos 000389962800032 Publication Date 2016-11-18
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0002-7863 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 13.858 Times cited 13 Open Access (down)
  Notes Approved Most recent IF: 13.858
  Call Number UA @ lucian @ c:irua:140298 Serial 4452
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Author Semkina, A.S.; Abakumov, M.A.; Abakumov, A.M.; Nukolova, N.V.; Chekhonin, V.P.
  Title Relationship between the Size of Magnetic Nanoparticles and Efficiency of MRT Imaging of Cerebral Glioma in Rats Type A1 Journal article
  Year 2016 Publication Bulletin of experimental biology and medicine Abbreviated Journal B Exp Biol Med+
  Volume 161 Issue 2 Pages 292-295
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract BSA-coated Fe3O4 nanoparticles with different hydrodynamic diameters (36 +/- 4 and 85 +/- 10 nm) were synthesized, zeta potential and T2 relaxivity were determined, and their morphology was studied by transmission electron microscopy. Studies on rats with experimental glioma C6 showed that smaller nanoparticles more effectively accumulated in the tumor and circulated longer in brain vessels. Optimization of the hydrodynamic diameter improves the efficiency of MRT contrast agent.
  Address
  Corporate Author Thesis
  Publisher Place of Publication New York Editor
  Language Wos 000380118500022 Publication Date 2016-07-07
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0007-4888 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 0.456 Times cited 5 Open Access (down)
  Notes Approved Most recent IF: 0.456
  Call Number UA @ lucian @ c:irua:144707 Serial 4684
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Author De Sloovere, D.; Safari, M.; Elen, K.; D'Haen, J.; Drozhzhin, O.A.; Abakumov, A.M.; Simenas, M.; Banys, J.; Bekaert, J.; Partoens, B.; Van Bael, M.K.; Hardy, A.
  Title Reduced Na2+xTi4O9 composite : a durable anode for sodium-ion batteries Type A1 Journal article
  Year 2018 Publication Chemistry of materials Abbreviated Journal Chem Mater
  Volume 30 Issue 23 Pages 8521-8527
  Keywords A1 Journal article; Condensed Matter Theory (CMT)
  Abstract Sodium-ion batteries (SIBs) are potential cost-effective solutions for stationary energy storage applications. Unavailability of suitable anode materials, however, is one of the important barriers to the maturity of SIBs. Here, we report a Na2+xTi4O9/C composite as a promising anode candidate for SIBs with high capacity and cycling stability. This anode is characterized by a capacity of 124 mAh g(-1) (plus 11 mAh g(-1) contributed by carbon black), an average discharge potential of 0.9 V vs Na/Na+, a good rate capability and a high stability (89% capacity retention after 250 cycles at a rate of 1 degrees C). The mechanisms of sodium insertion/deinsertion and of the formation of Na2+xTi4O9/C are investigated with the aid of various ex/in situ characterization techniques. The in situ formed carbon is necessary for the formation of the reduced sodium titanate. This synthesis method may enable the convenient synthesis of other composites of crystalline phases with amorphous carbon.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000453489300014 Publication Date 2018-11-29
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0897-4756 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 9.466 Times cited 7 Open Access (down)
  Notes ; This work was supported by the FWO (Research Foundation Flanders, project G040116). O.A.D. and A.M.A. are grateful to the Russian Science Foundation for financial support (Grant 17-73-30006). The authors acknowledge Pieter Samyn for Raman spectroscopy, Fulya Ulu Okudur for preliminary TEM, Bart Ruttens for XRD, Hilde Pellaers for SEM, Tom Haeldermans for elemental analysis, and Karen Leyssen and Vera Meynen for physisorption measurements. ; Approved Most recent IF: 9.466
  Call Number UA @ admin @ c:irua:156235 Serial 5227
Permanent link to this record
 

 
Author Hadermann, J.; Abakumov, A.M.
  Title Structure solution and refinement of metal-ion battery cathode materials using electron diffraction tomography Type A1 Journal article
  Year 2019 Publication And Materials Abbreviated Journal
  Volume 75 Issue 4 Pages 485-494
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract The applicability of electron diffraction tomography to the structure solution and refinement of charged, discharged or cycled metal-ion battery positive electrode (cathode) materials is discussed in detail. As these materials are often only available in very small amounts as powders, the possibility of obtaining single-crystal data using electron diffraction tomography (EDT) provides unique access to crucial information complementary to X-ray diffraction, neutron diffraction and high-resolution transmission electron microscopy techniques. Using several examples, the ability of EDT to be used to detect lithium and refine its atomic position and occupancy, to solve the structure of materials ex situ at different states of charge and to obtain in situ data on structural changes occurring upon electrochemical cycling in liquid electrolyte is discussed.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000480512600002 Publication Date 2019-08-05
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor Times cited 2 Open Access (down)
  Notes ; The following funding is acknowledged: Fonds Wetenschappelijk Onderzoek (grant No. G040116N); Russian Foundation of Basic Research (grant No. 17-03-00370-a). ; Approved Most recent IF: NA
  Call Number UA @ admin @ c:irua:161846 Serial 5397
Permanent link to this record
 

 
Author Kirsanova, M.A.; De Sloovere, D.; Karakulina, O.M.; Hadermann, J.; Van Bael, M.K.; Hardy, A.; Abakumov, A.M.
  Title Toward unlocking the Mn3+/Mn2+ redox pair in alluaudite-type Na2+2zMn2-z(SO4)3-x(SeO4)x cathodes for sodium-ion batteries Type A1 Journal article
  Year 2019 Publication Journal of solid state chemistry Abbreviated Journal J Solid State Chem
  Volume 277 Issue 277 Pages 804-810
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract In polyanion cathodes, the inductive effect alters the potential of a M(n+1)+/Mn+ redox couple (M – transition metal) according to the electronegativity of the X cation in the polyanion groups (XO4m+). To manipulate the operating potential, we synthesized a series of mixed sulfate-selenate alluaudites, with structure formulas Na2+2zMn2-z(SO4)(3-x)(SeO4)(x) and Na2.81Ni1.60(SO4)(1.43)(SeO4)(1.57). Their crystal structure was determined from powder X-ray diffraction data, revealing that the Mn-based alluaudites form solid solutions with the same crystal structure for x = 0.75; 1.125 and 1.5. Na2.81Ni1.60(SO4)(1.43)(SeO4)(1.57) is isostructural to the Mn-based alluaudites. Although the Na2+2zMn2-z(SO4)(3-x)(SeO4)(x) compound with the highest selenium content demonstrates a reversible discharge capacity of 60 mAh g(-1), only a small part of this electrochemical activity can be ascribed to the Mn3+/Mn2+ redox couple. The redox potential of the Mn3+/Mn2+ pair in Na2+2zMn2-z(SO4)(3-)x(SeO4)(x) decreases with increasing values of x, in agreement with the lower electronegativity of Se compared to that of S.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000481726300103 Publication Date 2019-07-24
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0022-4596 ISBN Additional Links UA library record; WoS full record
  Impact Factor 2.299 Times cited Open Access (down)
  Notes ; The authors thank the Russian Foundation for Basic Research for financial support (grant 17-03-00370), in addition to Research Foundation-Flanders (project No G040116). ; Approved Most recent IF: 2.299
  Call Number UA @ admin @ c:irua:162852 Serial 5401
Permanent link to this record
 

 
Author Fedotov, S.S.; Aksyonov, D.A.; Samarin, A.S.; Karakulina, O.M.; Hadermann, J.; Stevenson, K.J.; Khasanova, N.R.; Abakumov, A.M.; Antipov, E., V
  Title Tuning the crystal structure of A2CoPO4F(A=Li,Na) fluoride-phosphates : a new layered polymorph of LiNaCoPO4F Type A1 Journal article
  Year 2019 Publication European journal of inorganic chemistry Abbreviated Journal Eur J Inorg Chem
  Volume 2019 Issue 2019 Pages 4365-4372
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract Co-containing fluoride-phosphates are of interest in sense of delivering high electrode potentials and attractive specific energy values as positive electrode materials for rechargeable batteries. In this paper we report on a new Co-based fluoride-phosphate, LiNaCoPO4F, with a layered structure (2D), which was Rietveld-refined based on X-ray powder diffraction data [P2(1)/c, a = 6.83881(4) angstrom, b = 11.23323(5) angstrom, c = 5.07654(2) angstrom, beta = 90.3517(5) degrees, V = 389.982(3) angstrom(3)] and validated by electron diffraction and high-resolution scanning transmission electron microscopy. The differential scanning calorimetry measurements revealed that 2D-LiNaCoPO4F forms in a narrow temperature range of 520-530 degrees C and irreversibly converts to the known 3D-LiNaCoPO4F modification (Pnma) above 530 degrees C. The non-carbon-coated 2D-LiNaCoPO4F shows reversible electrochemical activity in Li-ion cell in the potential range of 3.0-4.9 V vs. Li/Li+ with an average potential of approximate to 4.5 V and in Na-ion cell in the range of 3.0-4.5 V vs. Na/Na+ exhibiting a plateau profile centered around 4.2 V, in agreement with the calculated potentials by density functional theory. The energy barriers for both Li+ and Na+ migration in 2D-LiNaCoPO4F amount to 0.15 eV along the [001] direction rendering 2D-LiNaCoPO4F as a viable electrode material for high-power Li- and Na-ion rechargeable batteries. The discovery and stabilization of the 2D-LiNaCoPO4F polymorph indicates that temperature influence on the synthesis of A(2)MPO(4)F fluoride-phosphates needs more careful examination with perspective to unveil new structures.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000484135500001 Publication Date 2019-08-07
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 1434-1948 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 2.444 Times cited Open Access (down)
  Notes ; This work is supported by the Russian Science Foundation (grant 17-73-30006). The authors greatly thank Dr. D. Rupasov for TG-DSC experiments, B. D. Shmykov and A. I. Manoilov for assistance with sample preparation, the Skoltech Center for Energy Science and Technology and the Moscow State University Program of Development up to 2020. J. Hadermann and O. M. Karakulina acknowledge support from the FWO under grant G040116N. ; Approved Most recent IF: 2.444
  Call Number UA @ admin @ c:irua:162857 Serial 5403
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Author Sanchez-Barriga, J.; Aguilera, I.; Yashina, L., V; Tsukanova, D.Y.; Freyse, F.; Chaika, A.N.; Callaert, C.; Abakumov, A.M.; Hadermann, J.; Varykhalov, A.; Rienks, E.D.L.; Bihlmayer, G.; Blugel, S.; Rader, O.
  Title Anomalous behavior of the electronic structure of (Bi1-xInx)2Se3across the quantum phase transition from topological to trivial insulator Type A1 Journal article
  Year 2018 Publication Physical review B Abbreviated Journal
  Volume 98 Issue 23 Pages 235110
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract Using spin- and angle-resolved photoemission spectroscopy and relativistic many-body calculations, we investigate the evolution of the electronic structure of (Bi1-xInx)(2)Se-3)(2)Se-3 bulk single crystals around the critical point of the trivial to topological insulator quantum-phase transition. By increasing x, we observe how a surface gap opens at the Dirac point of the initially gapless topological surface state of Bi2Se3, leading to the existence of massive fermions. The surface gap monotonically increases for a wide range of x values across the topological and trivial sides of the quantum-phase transition. By means of photon-energy-dependent measurements, we demonstrate that the gapped surface state survives the inversion of the bulk bands which occurs at a critical point near x = 0.055. The surface state exhibits a nonzero in-plane spin polarization which decays exponentially with increasing x, and which persists in both the topological and trivial insulator phases. Our calculations reveal qualitative agreement with the experimental results all across the quantum-phase transition upon the systematic variation of the spin-orbit coupling strength. A non-time-reversal symmetry-breaking mechanism of bulk-mediated scattering processes that increase with decreasing spin-orbit coupling strength is proposed as explanation.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000452322800003 Publication Date 2018-12-05
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor Times cited Open Access (down)
  Notes Approved no
  Call Number UA @ admin @ c:irua:156240 Serial 7462
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Author Takatsu, H.; Hernandez, O.; Yoshimune, W.; Prestipino, C.; Yamamoto, T.; Tassel, C.; Kobayashi, Y.; Batuk, D.; Shibata, Y.; Abakumov, A.M.; Brown, C.M.; Kageyama, H.
  Title Cubic lead perovskite PbMoO3 with anomalous metallic behavior Type A1 Journal article
  Year 2017 Publication Physical review B Abbreviated Journal
  Volume 95 Issue 15 Pages 155105
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract A previously unreported Pb-based perovskite PbMoO3 is obtained by high-pressure and high-temperature synthesis. This material crystallizes in the Pm3m cubic structure at room temperature, making it distinct from typical Pb-based perovskite oxides with a structural distortion. PbMoO3 exhibits a metallic behavior down to 0.1 K with an unusual T-sublinear dependence of the electrical resistivity. Moreover, a large specific heat is observed at low temperatures accompanied by a peak in C-P/T-3 around 10 K, in marked contrast to the isostructural metallic system SrMoO3. These transport and thermal properties for PbMoO3, taking into account anomalously large Pb atomic displacements detected through diffraction experiments, are attributed to a low-energy vibrational mode, associated with incoherent off-centering of lone-pair Pb2+ cations. We discuss the unusual behavior of the electrical resistivity in terms of a polaronlike conduction, mediated by the strong coupling between conduction electrons and optical phonons of the local low-energy vibrational mode.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000440605700001 Publication Date 2017-04-04
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor Times cited Open Access (down)
  Notes Approved no
  Call Number UA @ admin @ c:irua:167288 Serial 7743
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Author Alexander, C.T.; Abakumov, A.M.; Forslund, R.P.; Johnston, K.P.; Stevenson, K.J.
  Title Role of the carbon support on the oxygen reduction and evolution activities in LaNiO3 composite electrodes in alkaline solution Type A1 Journal article
  Year 2018 Publication ACS applied energy materials Abbreviated Journal
  Volume 1 Issue 4 Pages 1549-1558
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract Metal-air batteries and fuel cells show a great deal of promise in advancing low-cost, high-energy-density charge storage solutions for sustainable energy applications. To improve the activities and stabilities of electrocatalysts for the critical oxygen reduction and evolution reactions (ORR and OER, respectively), a greater understanding is needed of the catalyst/carbon interactions and carbon stability. Herein, we report how LaNiO3 (LNO) supported on nitrogen-doped carbon nanotubes (N-CNT) made from a high-yield synthesis lowers the overpotential for both the OER and ORR markedly to enable a low bifunctional window of 0.81 V at only a 51 mu g cm(-2) mass loading. Furthermore, the addition of LNO to the N-CNTs improves the galvanostatic stability for the OER by almost 2 orders of magnitude. The nanoscale geometries of the perovskites and the CNTs enhance the number of metal-support and charge transfer interactions and thus the activity. We use rotating ring disk electrodes (RRDEs) combined with Tafel slope analysis and ICP-OES to quantitatively separate current contributions from the OER, carbon oxidation, and even anodic iron leaching from carbon nanotubes.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000458705400020 Publication Date 2018-03-28
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 2574-0962 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor Times cited Open Access (down)
  Notes Approved no
  Call Number UA @ admin @ c:irua:157642 Serial 8487
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Author Shevchenko, V.A.; Glazkova, I.S.; Novichkov, D.A.; Skvortsova, I.; V. Sobolev, A.; Abakumov, A.M.; Presniakov, I.A.; Drozhzhin, O.A.; V. Antipov, E.
  Title Competition between the Ni and Fe redox in the O3-NaNi1/3Fe1/3Mn1/3O2 cathode material for Na-ion batteries Type A1 Journal article
  Year 2023 Publication Chemistry of materials Abbreviated Journal
  Volume 35 Issue 10 Pages 4015-4025
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
  Abstract Sodium-ion batteries are attracting great attention due to their low cost and abundance of sodium. The O3-type NaNi1/3Fe1/3Mn1/3O2 layered oxide material is a promising candidate for positive electrodes (cathodes) in Na-ion batteries. However, its stable electrochemical performance is restricted by the upper voltage limit of 4.0 V (vs Na/Na+), which allows for reversibly removing 0.5-0.55 Na+ per formula unit, corresponding to the capacity of 120-130 mAh.g(-1). Further reduction of sodium content inevitably accelerates capacity degradation, and this issue calls for a detailed study of the redox reactions that accompany the electrochemical (de)intercalation of a large amount of sodium. Here, we present operando and ex situ studies using powder X-ray diffraction and X-ray absorption spectroscopy combined with Fe-57 Mossbauer spectroscopy. Our approach reveals the sequence of the redox transitions that occur during the charge and discharge of O3-NaNi1/3Fe1/3Mn1/3O2. Our data show that in addition to nickel and iron cations oxidizing to M+4, a part of iron transforms into the “3 + delta” state owing to the fast electron exchange Fe3+ + Fe4+ <-> Fe4+ + Fe3+. This process freezes upon cooling the material to 35 K, producing Fe4+ cations, some of which occupy tetrahedral positions.
  Address
  Corporate Author Thesis
  Publisher Place of Publication Editor
  Language Wos 000985970200001 Publication Date 2023-05-04
  Series Editor Series Title Abbreviated Series Title
  Series Volume Series Issue Edition
  ISSN 0897-4756; 1520-5002 ISBN Additional Links UA library record; WoS full record; WoS citing articles
  Impact Factor 8.6 Times cited Open Access (down)
  Notes Approved Most recent IF: 8.6; 2023 IF: 9.466
  Call Number UA @ admin @ c:irua:197352 Serial 9013
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