• Title, Summary, Keyword: Solid-State Synthesis

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Modeling, Preparation, and Elemental Doping of Li7La3Zr2O12 Garnet-Type Solid Electrolytes: A Review

  • Cao, Shiyu;Song, Shangbin;Xiang, Xing;Hu, Qing;Zhang, Chi;Xia, Ziwen;Xu, Yinghui;Zha, Wenping;Li, Junyang;Gonzale, Paulina Mercedes;Han, Young-Hwan;Chen, Fei
    • Journal of the Korean Ceramic Society
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    • v.56 no.2
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    • pp.111-129
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    • 2019
  • Recently, all-solid-state batteries (ASSBs) have attracted increasing interest owing to their higher energy density and safety. As the core material of ASSBs, the characteristics of the solid electrolyte largely determine the performance of the battery. Thus far, a variety of inorganic solid electrolytes have been studied, including the NASICON-type, LISICON-type, perovskite-type, garnet-type, glassy solid electrolyte, and so on. The garnet Li7La3Zr2O12 (LLZO) solid electrolyte is one of the most promising candidates because of its excellent comprehensively electrochemical performance. Both, experiments and theoretical calculations, show that cubic LLZO has high room-temperature ionic conductivity and good chemical stability while contacting with the lithium anode and most of the cathode materials. In this paper, the crystal structure, Li-ion transport mechanism, preparation method, and element doping of LLZO are introduced in detail based on the research progress in recent years. Then, the development prospects and challenges of LLZO as applied to ASSBs are discussed.

Solid-state Synthesis of $Mg_2X$ (X=Si, Ge, Sn and Pb) via Bulk Mechanical Alloying

  • Aizawa, Tatsuhiko;Song, Renbo
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • pp.831-832
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    • 2006
  • Solid-state processing via the bulk mechanical alloying enables us to directly fabricate $Mg_2X$ semi-conductive material performs. Precise control of chemical composition leads to investigation on the dilution and enrichment of X in $Mg_2X$. Two types of solid-state reactivity are introduced: e.g. synthesis of $Mg_2Si$ from elemental mixture Mg-Si is nucleation-controlled process while synthesis of $Mg_2Sn$ from Mg-Sn, diffusion-controlled process. Thermoelectricity of these $Mg_2X$ is evaluated for discussion on the validity and effectiveness of this new PM route as a reliable tool for fabrication of thermoelectric compounds.

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Peculiarities of SHS and solid state synthesis of $ReBa_{2}Cu_{3}O_{7-x}$ materials

  • Sho, Dea-Wha;Li, Yingmei;Cho, Yong-Joon;Kim, Tae-Wan;Korobova, N.;Isaikina, O.;Mansurov, Z.;Baydeldinova, A.;Ksandopoulo, G.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.620-623
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    • 2001
  • The peculiarities of using Self-propagating High-temperature Synthesis (SHS) and solid state phase synthesis for production of high temperature superconductor materials are discussed. Oxide superconductors with general formula $ReBa_2$$Cu_3$$O_{7-x}$ (Re= Y, Yb, Sm, Nd) have been made with using barium oxide initial powder instead of traditional barium carbonate. X-ray powder diffraction showed a single phase orthorhombic perovskite structure was produced in all reactions. Phenomena observed during the grinding of the reactant mixture are presented. Mechano-chemical activation - as a pretreatment of the reactant mixture - strongly influences the kinetic parameters, the reaction mechanism, and the composition and structure of the final product.

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New Processing of LED Phosphors

  • Toda, Kenji
    • Transactions on Electrical and Electronic Materials
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    • v.13 no.5
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    • pp.225-228
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    • 2012
  • In order to synthesize LED phosphor materials, we have applied three novel synthesis techniques, "melt synthesis", "fluidized bed synthesis" and "vapor-solid hybrid synthesis", in contrast with the conventional solid state reaction technique. These synthesis techniques are also a general and powerful tool for rapid screening and improvements of new phosphor materials.

The SrLiAl3N4:Eu2+ Phosphor Synthesized by the Raw Material Model Obtained by DFT Calculations

  • Park, Woon Bae
    • Journal of the Korean Ceramic Society
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    • v.54 no.3
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    • pp.217-221
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    • 2017
  • Improvement studies of existing phosphors are needed for use in light emitting diodes (LEDs). Among the phosphors discovered recently, the SLA ($SrLiAl_3N_4:Eu^{2+}$) is a phosphor that has a narrow width. It is now known as a good red phosphor that meets the industry's needs for warm white (color temperature ranging from 2700 to 4000 K) and high CRI (> 80). However, SLA phosphors are obtained from difficult synthetic methods. All commercially available phosphors should be derived from the general solid state synthesis method. The phosphors produced by difficult synthetic methods will inevitably fall out of price competitiveness and will be scrapped. This study succeeded in synthesizing SLA ($SrLiAl_3N_4:Eu^{2+}$) phosphors by using a general solid phase synthesis method based on the reaction energy obtained from DFT calculations. As a result, we found an optimal solid state synthesis method for SLA phosphors.

Direct Solid State Synthesis of Zn4Sb3 by Hot Pressing and Thermoelectric Properties (열간 압축 공정에 의한 Zn4Sb3의 직접 고상 반응 합성 및 열전특성)

  • Ur Soon-Chul
    • Journal of Korean Powder Metallurgy Institute
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    • v.12 no.4
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    • pp.255-260
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    • 2005
  • Direct solid state synthesis by hot pressing has been applied in order to produce high efficiency $Zn_4Sb_3$ bulk specimens. Single phase $Zn_4Sb_3$ with 98.5% of theoretical density was successfully produced by direct hot pressing of elemental powders containing 1.2 at.% excess Zn. Thermoelectric properties as a function of temperature were investigated from room temperature to 600 K and compared with results of other studies. Transport properties at room temperature were also evaluated. Thermoelectric properties of single phase $Zn_4Sb_3$ materials produced by direct synthesis were measured and are comparable to the published data. Direct solid state synthesis by hot pressing provides a promising processing route in this material.

Synthesis of polymer - based inverted opal and transformation of its optical properties

  • Masalov, Vladimir M.;Dolganov, Pavel V.;Sukhinina, Nadezhda S.;Dolganov, Vladimir K.;Emelchenko, Gennadi A.
    • Advances in nano research
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    • v.2 no.1
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    • pp.69-76
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    • 2014
  • We have obtained opal-like photonic crystals based on opals and inverted opals exhibiting a shift of the selective reflection band toward longer and shorter wavelengths with respect to the diffraction band of the initial opal consisting of $SiO_2$ spheres. The contribution of frames forming three-dimensional periodic structures and that of fillers to the spectral arrangement of the diffraction bands has been determined.

Solid Phase Synthesis of 3-(4-Hydroxyphenyl)coumarin: Preliminary Experiments for Combinatorial Synthesis of Substituted 3-Phenylcoumarin Derivatives

  • Bae, Hoon;Kim, Hak-Sung
    • Archives of Pharmacal Research
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    • v.27 no.8
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    • pp.811-815
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    • 2004
  • Coumarin and its derivatives occur widely in nature. Many attempts were made for synthesis of various coumarin derivatives because of their interesting biological activities. In this study, solid phase synthetic approach of 3-(4-hydroxyphenyl)coumarin was achieved for combinatorial synthesis of substituted 3-phenylcoumarin analogues. Starting from 4-hydroxyphenylacetic acid methyl ester, release of 3-(4-hydroxypnehyl)coumarin from polymer support was accom-plished.

Solid-state metathetic synthesis of MWO4 (M=Zn, Co) particles assisted by microwave irradiation

  • Lim, Chang-Sung
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.20 no.6
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    • pp.295-300
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    • 2010
  • Metathetic route for the $MWO_4$ (M=Zn, Co) particles is a simple method of synthesis and a viable alternative method in a short time. $MWO_4$ (M=Zn, Co) particles were synthesized using solid-state metathetic (SSM) method with microwave irradiation. The $MWO_4$ (M=Zn, Co) particles were formed completely at $600^{\circ}C$ for 3 h. The crystallization process, thermal decomposition and morphology of the $MWO_4$(M= Zn, Co) particles were evaluated. The characteristics of the SSM reaction and the formation of a high lattice energy by-product NaCl were discussed.

Synthesis of Zn4Sb3 by Solid State Reaction and Hot Pressing, and Their Thermoeletric Properties (고상 합성과 진공 압축성형에 의한 Zn4Sb3의 제조 및 열전특성)

  • Ur Soon-Chul
    • Korean Journal of Materials Research
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    • v.15 no.7
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    • pp.473-479
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    • 2005
  • Thermoelectric $Zn_4Sb_3$ alloys were synthesized by a conventional powder metallurgy process consisting of solid state reaction and hot pressing. Single phase $Zn_4Sb_3$ was successfully produced by the annealing of cold compact starting with the mixed elemental powders, and subsequent hot pressing yielded single phase bulk specimens without microcracks. Phase transformations in this alloy system during synthesis were investigated using XRD, SEM and EDS. Thermoelectric properties as a function of temperature were investigated from room temperature to 600 K and compared with results of analogue studies. Transport properties at room temperature were also evaluated. Thermoelectric properties of single phase $Zn_4Sb_3$ materials produced by this process are comparable to the published data. Synthesis by solid state reaction and hot pressing offers a potential processing route to produce a bulk $Zn_4Sb_3$