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Towards understanding the influence of Mg content on phase transformations in the La3-xMgxNi9 alloys by in-situ neutron powder diffraction study

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Progress in Natural Science:Materials International 2021年第5期31卷 698-704页

作者： Chu Bin Wan R.V.Denys V.A.Yartys Institute for Energy Technology University of Science and Technology Beijing HYSTORSYS AS

The present work is focused on the studies of the phase-structural transformations in the La3-xMgxNi9(x = 1.0, 1.1 and 1.2) alloys as active materials of negative electrodes in the Nickel-Metal Hydride(Ni/MH) batteries. The phase equilibria and phase-structural transformations in the alloys were probed by in situ neutron powder diffraction(NPD) at the temperatures ranging from 300 K to 1273 K using the measurements of the equilibrated alloys at 8 setpoint temperatures of 300, 973, 1073, 1123, 1173, 1223, 1248 and 1273 *** by induction melting initial alloys were found to be multi-phase structured, containing up to 6 individual intermetallic compounds with different stoichiometric compositions. With the increase of the temperature and holding time, various transformations took place in the studied alloys. These included the formations and transformations of super-stacking intermetallics with variable ratios(La + Mg)/Ni, 1:3, 2:7 and 5:*** increasing temperatures, several systematic changes took place.(a) Abundances of(La,Mg)2Ni4AB2and(La,Mg)Ni3AB3type intermetallics gradually decreased before they melted/decomposed above 1073 K;(b) The(La,Mg)2Ni7A2B7type intermetallics began to decrease in abundances above 1123 K;(c) The transformation in the(La,Mg)5Ni19intermetallics from 3 R to 2 H proceeded above 1223 *** increase of Mg content had no obvious influence on(La,Mg)2Ni4and(La,Mg)2Ni7phases, and corresponding reactions R1 and R3 took place at the same temperatures as in the La–Ni system. However, with increasing Mg content the melting point of(La,Mg)5Ni19phase increased while the melting point of the(La,Mg)Ni3phase it decreased, leading to the variation of the reaction temperatures of the corresponding *** present study will assist in optimizing phase-structural composition of the alloys in the La–Mg–Ni system which contain Mg-modified layered structures by tailoring the high temperature annealing conditions.

关键词： Hydrogen absorbing materials neutron powder diffraction In situ study La–Mg–Ni alloy Phase transformation

Formation of the structure-Ⅱgas hydrate from low-concentration propane mixed with methane

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Chinese Journal of Chemical Engineering 2023年第6期58卷 306-314页

作者： Sanya Du Xiaomin Han Wenjiu Cai Jinlong Zhu Xiaobai Ma Songbai Han Dongfeng Chen Yusheng Zhao Hui Li Hailong Lu Xiaohui Yu Beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing University of Chemical TechnologyBeijing 100029China National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China College of Engineering Peking UniversityBeijing 100871China Beijing International Center for Gas Hydrate School of Earth and Space SciencesPeking UniversityBeijing 100871China Department of Physics Southern University of Science and Technology(SUSTech)Shenzhen 518055China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou 511458China Department of Nuclear Physics China Institute of Atomic EnergyBeijing 102413China Academy for Advanced Interdisciplinary Studies Southern University of Science and Technology(SUSTech)Shenzhen 518055China Songshan Lake Materials Laboratory Dongguan 523808China

It has been recognized that a small amount of propane mixed with methane can change greatly in not only the thermodynamics but also the structural properties of gas ***,its mechanism is still not well understood *** this research,structure-Ⅱ(sⅡ)hydrate is synthesized using a methanepropane gas mixture with an initial mole ratio of 99:1,and it is found that large(5~(12)6~4)cages are cooccupied by multiple gases based on the rigid structure analysis of neutron diffraction *** first principles calculation and molecular dynamics simulation are conducted to uncover the molecular mechanism for sⅡmethane-propane hydrate formation,revealing that the presence of propane inhibits the formation of structure-Ⅰ(sⅠ)hydrate but promotes sⅡhydrate *** results help to understand the accumulation mechanism of natural gas hydrate and benefit to optimize the condition for gas storage and transportation in hydrate form.

关键词： Multiple guest molecules Clathrates neutron powder diffraction Structural transformation Molecular mechanism

Effects of charging rates on LiNi_(0.6)Mn_(0.2)Co_(0.2)O_(2)(NMC622)/graphite Li-ion cells

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Journal of Energy Chemistry 2021年第5期30卷 121-126页

作者： Xianyang Wu Yaocai Bai Zhenglong Li Jue Liu Kejie Zhao Zhijia Du Energy and Transportation Science Division Oak Ridge National LaboratoryOak RidgeTN 37830USA School of Mechanical Engineering Purdue UniversityWest LafayetteIN 47907USA neutron Scattering Division Oak Ridge National LaboratoryOak RidgeTN 37830USA

Enabling fast charging capability of lithium-ion battery is of great importance to widespread adoption of electric *** the charging rates from state-of-the-art 2 C(30 min)to 6 C(10 min)requires deep understanding on the cell aging *** this study,400 mAh pouch cells are cycled at 1 C,4 C and 6 C charging rates with 1 C discharging *** fading,cathode structural changes,Li inventory loss,electrolyte composition changes and Li plating on graphite electrodes are thoroughly studied by various characterization *** rapid capacity fading in cells at 6 C charging rate is mainly due to Li inventory loss from cathode structure and metallic Li plating on graphite electrode at higher charging ***-mortem analysis also revealed changes in electrolyte such as increased salt molarity and transesterification during fast charging.

关键词： Li-ion cells Fast charging Post-test analysis neutron powder diffraction

Impact of In^(3+) cations on structure and electromagnetic state of M-type hexaferrites

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Journal of Energy Chemistry 2022年第6期31卷 667-676,I0018页

作者： Vitalii Alexandrovich Turchenko Sergei Valentnovich Trukhanov Vladmir Grigor'evich Kostishin Francua Damay Florance Porcher Denis Sergeevich Klygach Maxim Grigor'evich Vakhitov Lyudmila Yur'evna Matzui Olena Sergeevna Yakovenko Bernat Bozzo Ignasi Fina Munirah Abdullah Almessiere Yassine Slimani Abdulhadi Baykal Di Zhou Alex Valentinovich Trukhanov Joint Institute for Nuclear Research 6 Joliot-Curie Str.Dubna 141980Russia South Ural State University 76Lenin Av.Chelyabinsk 454080Russia Donetsk Institute of Physics and Technology named after O.O.Galkin of the NASU 46 Nauki Av.Kiev 03680Ukraine SSPA“Scientific and Practical Materials Research Centre of NAS of Belarus” 19 P.Brovki str.Minsk 220072Belarus National University of Science and Technology“MISiS” Leninsky av.4Moscow 119049Russia Laboratoire Leon Brillouin UMR12 CEA-CNRSB̂at.563 CEA SaclayGif sur YvetteCedex 91191France Ural Federal University named after the First President of Russia B.N.Yeltsin Yekaterinburg 620002Russia Taras Shevchenko National University of Kyiv Volodymyrs’ka str.64/13Kyiv 01601Ukraine Institut de Ciencia de Materials de Barcelona-CSIC Campus de la UABBellaterraBarcelona 08193Spain Department of Biophysics Institute for Research and Medical Consultations(IRMC)Imam Abdulrahman Bin Faisal UniversityP.O.Box 1982Dammam 31441Saudi Arabia Department of Nanomedicine Institute for Research and Medical Consultations(IRMC)Imam Abdulrahman Bin Faisal UniversityP.O.Box 1982Dammam 31441Saudi Arabia Electronic Materials Research Laboratory Key Laboratory of the Ministry of Education&International Center for Dielectric ResearchSchool of Electronic Science and EngineeringXi’an Jiaotong UniversityXi'an 710049ShannxiChina Department of Physics College of ScienceImam Abdulrahman Bin Faisal UniversityP.O.Box 1982Dammam 31441Saudi Arabia

The solid solutions of In^(3+) doped M-type strontium hexaferrites were produced using a conventional solid-state reaction method,and Rietveld analysis of the neutron diffraction patterns was ***^(3+) cations occupy octahedral (4f_(Ⅵ)and 12 k) and tetrahedral (4f_(Ⅳ)) positions (SG=P6_(3)/mmc(No.194)).The average particle size is 837–650 *** tempearature (T_(C)) of the compounds monotonically decreased down to~520 K with increasing x.A frustrated magnetic state was detected from ZFC and FC *** magnetization (M_(s)) and effective magnetocrystalline anisotropy coefficient (k_(eff)) were determined using the law of approach to saturation.A real permittivity (ε″) maximum of~3.3 at~45.5 GHz and an imaginary permittivity (ε′) of~1.6 at~42.3 GHz were observed for x=0.1.A real permeability (μ′) maximum of~1.5 at~36.2 GHz was observed for x=0.Aμ″imaginary permeability maximum of~0.8 at~38.3 GHz was observed for x=*** interpretation of the results is based on the type of dielectric polarization and the natural ferromagnetic resonance features.

关键词： Doped strontium hexaferrites neutron powder diffraction Magnetic properties Permittivity Permeability

The critical role of spin rotation in the giant magnetostriction of La(Fe,Al)_(13)

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Science China Materials 2021年第5期64卷 1238-1245页

作者： Yuzhu Song Rongjin Huang Ji Zhang Shantao Zhang Qingzhen Huang Shouguo Wang Yong Jiang Laifeng Li Xianran Xing Jun Chen Beijing Advanced Innovation Center for Materials Genome Engineering School of Mathematics and PhysicsUniversity of Science and Technology BeijingBeijing 100083China Key Laboratory of Cryogenics Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190China National Laboratory of Solid State Microstructures and Department of Materials Science and Engineering College of Engineering and Applied Science&Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China NIST Center for neutron Research National Institute of Standards and TechnologyGaithersburg MD20899-6102USA School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China

As an efficient converter between electromagnetic and mechanical energies, magnetostriction is an intriguing property for not only fundamental studies but also technological applications. However, the understanding of its microscopic origin remains challenging, which is critical for the development of magnetostriction materials. Here, the critical role of spin rotation in the giant magnetostriction of La(Fe,Al)_(13) is first revealed by the in-situ magnetic and temperature field of neutron powder diffraction. The giant magnetostriction originates from magnetic-field-driven spin moment rotation of canting structure, in which the sharp increase of ferromagnetic component causes the elongation of icosahedron inside of lattice. Furthermore, it is the first time to reveal the accurate canting antiferromagnetic structure in La(Fe,Al)_(13). The present study provides a new strategy, i.e., the spin rotation, for exploring new magnetostriction functional materials.

关键词： magnetostriction magnetic-field-induced spin rotation magnetic structure neutron powder diffraction

A High-Performance Solid-State Na–CO_(2)Battery with Poly(Vinylidene Fluoride-co-Hexafluoropropylene)−Na_(3.2)Zr_(1.9)Mg_(0.1)Si_(2)PO_(12)Electrolyte

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Energy & Environmental Materials 2023年第3期6卷 87-95页

作者： Liang Lu Chunwen Sun Jian Hao Zelin Wang Sergio F.Mayer Maria Teresa Fernandez-Diıaz Jose Antonio Alonso Bingsuo Zou School of Chemical&Environmental Engineering China University of Mining and Technology-BeijingBeijing 100083China School of Physical Science and Technology Guangxi UniversityNanning 530004China State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering Ningxia UniversityYinchuan 750021China Instituto de Ciencia de los Materiales de Madrid CSICE-28049Cantoblanco-MadridSpain Institut Laue Langevin Grenoble F-38042France Guangxi Key Lab of Processing for Nonferrous Metals and Featured Materials and Key lab of new Processing Technology for Nonferrous Metals and Materials Ministry of EducationSchool of ResourcesEnvironments and MaterialsGuangxi UniversityNanning 530004China

The recovery and utilization of carbon dioxide(CO_(2))is the key to achieve the targets of peak carbon dioxide emissions and carbon *** Na-CO_(2)battery made with cheap alkali metal sodium and greenhouse gas CO_(2)is an effective strategy to consume CO_(2)and store clean renewable ***,the liquid electrolyte volatilization in the open battery system and inevitable dendrite growth restrict the application of Na-CO_(2)*** this work,magnesium-doped Na_(3)Zr_(2)Si_(2)PO_(12)(NZSP)was studied as a solid electrolyte for solid-state Na-CO_(2)*** ionic conductivity of Na_(3.2)Zr_(1.9)Mg_(0.1)Si_(2)PO_(12)reaches 1.16 mS cm^(−1)at room temperature by replacing Zr ions in Na_(3.2)Zr_(1.9)Mg_(0.1)Si_(2)PO_(12)with Mg ions,and the structural changes are analyzed by neutron powder *** composite electrolyte consisting of highly conductive Na_(3.2)Zr_(1.9)Mg_(0.1)Si_(2)PO_(12)and high processability poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)is utilized for the first time to assemble a solid-state Na-CO_(2)*** cell shows a full discharge capacity of 7720 mAh g^(−1)at 200 mA g^(−1).The middle gap voltage is lower than 2 V after 120 cycles at 200 mA g^(−1)and at a cut-off capacity of 500 mAh g^(−1).This work demonstrates a promising strategy to design high-performance solid-state Na-CO_(2)batteries.

关键词： cycling stability ion transport Mg-doped NZSP neutron powder diffraction solid-state Na-CO_(2)batteries

neutron diffraction study on composite compound Nd_2 Co_7

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Chinese Physics B 2011年第10期20卷 329-334页

作者：杨育奇李冠男王通黄清镇高庆庆李静波刘光耀骆军饶光辉 Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Centre for neutron Research National Institute of Standards and Technology

The crystallographic and the magnetic structures of the composite compound Nd2Co7 at 300 K are investigated by a combined refinement of X-ray diffraction data and high-resolution neutron diffraction data. The compound crystallizes into a hexagonal Ce2NiT-type structure and consists of alternately stacking MgZn2-type NdCo2 and CaCus-type NdCo5 structural blocks along the c axis. A magnetic structure model with the moments of all atoms aligning along the c axis provides a satisfactory fitting to the neutron diffraction data and coincides with the easy magnetization direction revealed by the X-ray diffraction experiments on magnetically pre-aligned fine particles. The refinement results show that the derived atomic moments of the Co atoms vary in a range of 0.7 μB-1.1 μB and the atomic moment of Nd in the NdCo5 slab is close to the theoretical moment of a free trivalent Nd3＋ ion, whereas the atomic moment of Nd in the NdCo2 slab is much smaller than the theoretical value for a free Nd3＋ ion. The remarkable difference in the atomic moment of Nd atoms between different structural slabs at room temperature is explained in terms of the magnetic characteristics of the NdCo2 and NdCo5 compounds and the local chemical environments of the Nd atoms in different structural slabs of the Nd2Co7 compound.

关键词： Nd2Co7 neutron powder diffraction magnetic structure crystal structure

MgCo2-D2 and MgCoNi-D2 systems synthesized at high pressures and interaction mechanism during the HDDR processing

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Progress in Natural Science:Materials International 2017年第1期27卷 74-80页

作者： Chubin Wan V.E.Antonov R.V.Denys V.I.Kulakov V.A.Yartys University of Science and Technology Beijing Institute for Energy Technology Institute of Solid State Physics Russian Academy of Sciences HYSTORSYS AS Norwegian University of Science and Technology

MgCo2and MgNiCo crystallize with hexagonal Laves type intermetallic structures of the C14 type and do not form hydrides at ambient hydrogen pressures. However, applying high hydrogen pressures in the GPa range forces the hydrogen absorption and leads to the formation of multi-phase compositions, which contain approximately 2.5 atoms H per formula unit of MgCo2or MgNiCo and remain thermally stable under normal *** hydrogenation of MgCo2resulted in its decomposition to a ternary Mg2CoD5deuteride and metallic cobalt. Phase-structural transformations accompanying the vacuum desorption of deuterium in the temperature range of 27–500 °C were studied using in situ neutron powder diffraction. The investigation showed a complete recovery of the initial MgCo2intermetallic via a Hydrogenation-Disproportionation-Desorption-Recombination process. At 300°C, the Mg2CoD5deuteride first decomposed to elementary Mg and hexagonal Co. At 400°C, a MgCo phase was formed by interaction between Mg and Co. At the highest processing temperature of 500°C, a solid-state interaction of MgCo and Co resulted in the recovery of the initial *** interaction of MgNiCo with deuterium under the synthesis conditions of 2.8 GPa and 200 °C proceeded in a more complex way. A very stable ternary deuteride MgNi2D3was leached away while Co was separated in the form of Mg2CoD5and the remaining nickel formed a solid solution with Co with the approximate composition *** thermal desorption of deuterium from MgCo2D2.5and from MgNiCoD2.5has been studied by Thermal Desorption Spectroscopy with deuterium released into a closed volume. The observed effects nicely correlate with changes in the phase structural composition of the hydrides ***2is a new example of the hydrogen storage alloy, in which a successful HDDR processing results in the reversible formation of the initial intermetallic at much lower temperatures than in the equilibrium phase diagram of the Mg-Co system.

关键词： Intermetallics Hydrogen storage materials neutron powder diffraction High pressure synthesis Phase-structural transformations Magnesium Cobalt Nickel

Oxygen vacancy migration and its lattice structural origin in A-site non-stoichiometric bismuth sodium titanate perovskites

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Journal of Materiomics 2022年第3期8卷 719-729页

作者： Jing Shi Xiao Liu Fangyuan Zhu Wenchao Tian Yuanhua Xia Tangyuan Li Rongrong Rao Tao Zhang Laijun Liu Key Laboratory of Electronic Equipment Structure Design(MOE) School of Mechano-Electronic EngineeringXidian UniversityXi'an710071China School of Materials Science and Engineering Xi'an University of Science and TechnologyXi'an710054China Shanghai Synchrotron Radiation Facility Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai201204China Institute of Nuclear Physics and Chemistry China Academy of Engineering PhysicsMianyang621900China Frontier Institute of Science and Technology Xi'an Jiaotong UniversityXi'an710049China College of Science Xi'an University of Science and TechnologyXi'an710054China Key Laboratory of Nonferrous Materials and New Processing Technology(MOE) College of Materials Science and EngineeringGuilin University of TechnologyGuilin541004China

Off-stoichiometry of perovskite structural Bi0.5Na0.5TiO3(BNT)ferroelectrics can give rise to considerable oxide-ion *** inherent structural characteristics are urgent to be resolved due to its particular sensitivity of the conduction mechanism to the nominal composition and synthesis ***,a thorough study of the temperature-dependent neutron,X-ray diffraction and Raman spectrum is carried out on a series of equivalently substituted A-site deficient non-stoichiometric and pristine *** transition and defect association are systemically investigated in these dominated rhombohedral phases at room temperature,associated with well saturated ferroelectric *** structural evolution identified by Rietveld refinements and the origin of the electrical performance are clarified at elevated temperatures,focusing on the subtle distortions of ionic displacements,oxygen octahedral tilts and local chemical environments for oxygen *** ion migration ability mediated by oxygen vacancies that are not energetically favorable in BNT mainly depends on the external substitutional disorder,and is strongly affected by the dopant *** with the lone pair substitution concept,superior oxide ionic conductivity is achieved,and an alternative strategy is provided in designing BNT based oxide ion conductors.

关键词： Ferroelectrics Bismuth sodium titanate Oxide ion conductors neutron powder diffraction Oxygen vacancy