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In-situ construction of a thermodynamically stabilized interface on the surface of single crystalline Ni-rich cathode materials via a onestep molten-salt route

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Nano Research 2023年第5期16卷 6771-6779页

作者： Huiya Yang Xiangbang Kong Jiyang Li Pengpeng Dai Jing Zeng Yang Yang Jinbao Zhao State Key Laboratory of Physical Chemistry of Solid Surfaces Collaborative Innovation Centre of Chemistry for Energy MaterialsState-Province Joint Engineering Laboratory of Power Source Technology for New Energy VehicleEngineering Research Center of Electrochemical TechnologyMinistry of EducationCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China

Nickel rich LiNi_(x)Co_(y)Mn_(1−x−y)O_(2)cathode materials have been studied extensively to increase the energy density of lithium-ion batteries(LIBs)due to their advantages of high capacity and low ***,the anisotropic crystal expansion and contraction inside the secondary particles would cause detrimental micro-cracks and severe parasitic reactions at the electrode/electrolyte interface during cycling,which severely decreases the stability of crystalline structure and cathodeelectrolyte interphase and ultimately affects the calendar life of ***,a thermodynamically stabilized interface is constructed on the surface of single-crystalline Ni-rich cathode materials(SC811@RS)via a facile molten-salt route to suppress the generation of microcracks and interfacial parasitic side reactions *** functional theory calculations show that the formation energy of interface layer(−1.958 eV)is more negative than that of bulk layered structure(−1.421 eV).Such a thermodynamically stable protective layer can not only prevent the direct contact between highly reactive LiNi_(x)Co_(y)Mn_(1−x−y)O_(2)and electrolyte,but also mitigate deformation of structure caused by stress thus strengthening the mechanical *** spectra further confirm the excellent structural reversibility and reaction homogeneity of SC811@RS at particle,electrode,time ***,SC811@RS cathode material delivers significantly improved cycling stability(high capacity retention of 92%after 200 cycles at 0.5 C)compared with polycrystalline LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(82%).

关键词： LiNi_(x)Co_(y)Mn_(1−x−y)O_(2) single crystalline polycrystalline cathode lithium-ion battery

Extraordinary Transport Behaviors of La_(0.67)Sr_ ( 0.33)Mn_ (1-x)Cr_xO_3(0.00≤x≤0.30)

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Journal of Rare Earths 2006年第3期24卷 332-336页

作者：宋启祥刘宁严国清童伟孙阳 Materials Laboratory Suzhou College Suzhou 234000 China Materials Laboratory Suzhou College Suzhou 234000 China Structure Research Laboratory University of Science and Technology of China Hefei 230026 China Structure Research Laboratory University of Science and Technology of China Hefei 230026 China

M-T curves, ρ-T curves and MR-T curves of La0.67Sr0.33Mn1-xCrxO3（0.00≤ x ≤0.30） were studied. Experimental results indicate that the substitution of Cr on Mn sites is impotent in driving Tc, but with an increase of Cr content, there appear two peaks in resistivity and MR response, thus the temperature range of CMR response is significantly broadened. The extraordinary transport behavior and the abnormal CMR effect could be the results of coexistence and competition of Mn^3 ＋ -O-Mn^4 ＋ and Mn^3＋ -O-Cr^3 ＋ channels.

关键词： coherence physics transport CMR effect polycrystalline rare earths

Machine learning enabled autonomous microstructural characterization in 3D samples

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npj Computational Materials 2020年第1期6卷 1654-1662页

作者： Henry Chan Mathew Cherukara Troy D.Loeffler Badri Narayanan Subramanian K.R.S.Sankaranarayanan Center for Nanoscale Materials Argonne National LaboratoryArgonneILUSA Department of Mechanical Engineering University of LouisvilleLouisvilleKYUSA Department of Mechanical and Industrial Engineering University of Illinois at ChicagoChicagoILUSA

We introduce an unsupervised machine learning(ML)based technique for the identification and characterization of microstructures in three-dimensional(3D)samples obtained from molecular dynamics simulations,particle tracking data,or *** technique combines topology classification,image processing,and clustering algorithms,and can handle a wide range of microstructure types including grains in polycrystalline materials,voids in porous systems,and structures from self/directed assembly in soft-matter complex *** technique does not require a priori microstructure description of the target system and is insensitive to disorder such as extended defects in polycrystals arising from line and plane *** demonstrate quantitively that our technique provides unbiased microstructural information such as precise quantification of grains and their size distributions in 3D polycrystalline samples,characterizes features such as voids and porosity in 3D polymeric samples and micellar size distribution in 3D complex *** demonstrate the efficacy of our ML approach,we benchmark it against a diverse set of synthetic data samples representing nanocrystalline metals,polymers and complex fluids as well as experimentally published characterization *** technique is computationally efficient and provides a way to quickly identify,track,and quantify complex microstructural features that impact the observed material behavior.

关键词： microstructure polycrystalline porosity

Mechanical pressing method for making high-quality perovskite single crystals

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Journal of Semiconductors 2023年第11期44卷 1-4页

作者： Chenglin Wang Jie Sun Jiangzhao Chen Cong Chen Liming Ding State Key Laboratory of Reliability and Intelligence of Electrical Equipment School of Materials Science and EngineeringHebei University of TechnologyTianjin 300401China Faculty of Materials Science and Engineering Kunming University of Science and TechnologyKunming 650093China Center for Excellence in Nanoscience(CAS) Key Laboratory of Nanosystem and Hierarchical Fabrication(CAS)National Center for Nanoscience and TechnologyBeijing 100190China Macao Institute of Materials Science and Engineering(MIMSE) Macao University of Science and TechnologyMacao 999078China

Halide perovskites show excellent photovoltaic properties[1−4].However,the preparation of high-quality perovskite crystals remains a great challenge,which limits their *** materials applied to photodetectors mainly include polycrystalline thin films and single *** solution methods are used to prepare polycrystalline thin films,and the films are full of defects such as voids and grain boundaries[5−7].Compared to polycrystalline thin films,perovskite single crystals possess high crystallinity and low defect density[8−10].Photodetectors based on perovskite single crystals exhibit excellent performance[11].However,the size limitation of single crystals hinders their application in photodetectors[12].

关键词： perovskite polycrystalline hinder

Highly Textured N-Type SnSe Polycrystals with Enhanced Thermoelectric Performance

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Research 2019年第1期2019卷 251-260页

作者： Peng-Peng Shang Jinfeng Dong Jun Pei Fu-Hua Sun Yu Pan Huaichao Tang Bo-Ping Zhang Li-Dong Zhao Jing-Feng Li State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China College of Chemistry and Material Science Shandong Agricultural UniversityTai’an 271018China The Beijing Municipal Key Laboratory of New Energy Materials and Technologies School of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing 100083China School of Materials Science and Engineering Beihang UniversityBeijing 100191China

Thermoelectric materials,which directly convert heat into electricity based on the Seebeck effects,have long been investigated for use in semiconductor refrigeration or waste heat *** them,SnSe has attracted significant attention due to its promising performance in both p-type and n-type crystals;in particular,a higher out-of-plane ZT value could be achieved in ntype SnSe due to its 3D charge and 2D phonon *** this work,the thermoelectric transport properties of n-type polycrystalline SnSe were investigated with an emphasis on the out-of-plane transport through producing textural *** textures were fabricated using mechanical alloying and repeated spark plasma sintering(SPS),as a kind of hot pressing,aimed at producing strong anisotropic transports in n-type polycrystalline SnSe as that in crystalline *** show that the lowest thermal conductivity of 0.36 Wm^(-1) K^(-1) was obtained at 783 K in perpendicular to texture ***,the electrical transport properties are less anisotropic and even nearly isotropic,and the power factors reach 681.3μWm^(-1) K^(-2) at 783 K along both parallel and perpendicular *** combination of large isotropic power factor and low anisotropic thermal conductivity leads to a maximum ZT of 1.5 at 783 *** high performance elucidates the outstanding electrical and thermal transport behaviors in n-type polycrystalline SnSe,and a higher thermoelectric performance can be expected with future optimizing texture in n-type polycrystalline SnSe.

关键词： alloying polycrystalline anisotropic

Quantitative multi-phase-field modeling of non-isothermal solidification in hexagonal multicomponent alloys

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China Foundry 2022年第3期19卷 263-274页

作者： Yong-biao Wang Ming-guang Wei Xin-tian Liu Cong Chen Jian-xiu Liu Yu-juan Wu Shuai Dong Li-ming Peng Henan Key Laboratory of Intelligent Manufacturing of Mechanical Equipment Zhengzhou University of Light IndustryZhengzhou 450002China National Engineering Research Center of Light Alloy Net Forming and State Key Laboratory of Metal Matrix Composite Shanghai Jiao Tong UniversityShanghai 200240China Luoyang Institute of Special Materials Research Luoyang 471600HenanChina

A quantitative multi-phase-field model for non-isothermal and polycrystalline solidification was developed and applied to dilute multicomponent alloys with hexagonal close-packed *** effects of Lewis coefficient and undercooling on dendrite growth were investigated *** show that large Lewis coefficients facilitate the release of the latent heat,which can accelerate the dendrite growth while suppress the dendrite tip *** greater the initial undercooling,the stronger the driving force for dendrite growth,the faster the growth rate of dendrites,the higher the solid fraction,and the more serious the solute *** simulated dendrite growth dynamics are consistent with predictions from the phenomenological theory but significantly deviate from the classical JMAK theory which neglects the soft collision effect and mutual blocking among ***,taking the Mg-6Gd-2Zn(wt.%)alloy as an example,the simulated dendrite morphology shows good agreement with experimental results.

关键词： multi-phase-field model non-isothermal solidification polycrystalline multicomponent alloys dendrite growth microstructure

Design and Manufacturing of Ultra-Hard Micro-Milling Tool

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Transactions of Tianjin University 2014年第6期20卷 415-421页

作者：战忠波李亮何宁卞荣赵孟 College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics

Based on the study of existing typical micro-milling tools and the actual demand for micro-milling tools, the P3 design principle and design flow for ultra-hard micro-milling tool were introduced to give basic guidance for the optimization of micro-milling tools. Then, according to the P3 design flow, the manufacturing process of polycrystalline diamond(PCD) micro-milling tool was proposed, and the PCD micro-milling tool with diameter of 0.5 mm was developed. Finally, the micro-milling test on the slot was carried out to study the milling performance of PCD micromilling tool.

关键词： micro-milling micro-milling tool ultra-hard material polycrystalline diamond (PCD) finite elementanalysis

Preparation of High Quality p-Type Diamond Thin Films by Thermal Chemical Vapor Deposition

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Chinese Physics Letters 1991年第4期8卷 203-206页

作者： YU San JIN Zengsun LÜ Xianyi ZOU Guangtian Institute of Atomic and Molecular Physics Jilin UniversityChangchun 130023

P-type semiconducting polycrystalline diamond thin films doped with boron were synthesized on single crystalline silicon substrate by thermal chemical vapor deposition from a tungsten filament and placing boron-contained substance(boron nitride or elemental boron)on sample *** films were determined to be the high quality diamond by Raman spectroscopy,X-ray diffraction and scanning electron microscope *** doping properties of boron were measured by Hall method and infrared absorption.

关键词： boron Diamond polycrystalline

ANTIMONY INDUCED CRYSTALLIZATION OF AMORPHOUS SILICON

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Acta Metallurgica Sinica(English Letters) 2007年第3期20卷 167-170页

作者： Y. Wang H.Z. Li C.N. Yu G.M. Wu I. Gordon P. Schattschneider O. Van Der Biest School of Science Beijing Institute of Petro-Chemical Technology Beijing 102617 China Center of Engineering Education Beijing Institute of Petro-Chemical Technology Beijing 102617 China School of Materials Science and Engineering Beijing Institute of Pctro-Chcmical Technology Beijing 102617 China Development of Technique Interuniversity Micro Electronics Center B-3001 Leuven Belgium School of Materials Science and Engineering Technische Universitat Wien A-1040 Wien Austria School of Materials Science and Engineering Kathofieke Universiteit Leuven B-3001 Heverlee （Leuven） Belgium

Antimony induced crystallization of PVD （physics vapor deposition） amorphous silicon can be observed on sapphire substrates. Very large crystalline regions up to several tens of micrometers can be formed. The Si diffraction patterns of the area of crystaUization can be observed with TEM （transmission electron microscopy）. Only a few and much smaller crystals of the order of 1 μm were formed when the antimony layer was deposited by MBE （molecular beam epitaxy） compared with a layer formed by thermal evaporation. The use of high vacuum is essential in order to observe any Sb induced crystallization at all. In addition it is necessary to take measures to limit the evaporation of the antimony.

关键词： antimony polycrystalline silicon thin film