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Understanding the failure mechanism towards developing high-voltage single-crystal Ni-rich Co-free cathodes

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Green Energy & Environment 2024年第6期9卷 1045-1057页

作者： jixue Shen Bao Zhang Changwang Hao Xiao li Zhiming Xiao Xinyou He Xing Ou Engineering Research Center of the Ministry of Education for Advanced Battery Materials School of Metallurgy and EnvironmentCentral South UniversityChangsha410083China Zhejiang Power New Energy Co. Ltd.Zhuji311899China Material Science and Chemistry Engineering College China University of GeosciencesWuhan430074China

Benefited from its high process feasibility and controllable costs,binary-metal layered structured liNi_(0.8)Mn_(0.2)O_(2)(NM)can effectively alleviate the cobalt supply crisis under the surge of global electric vehicles(EVs)sales,which is considered as the most promising nextgeneration cathode material for lithium-ion batteries(liBs).However,the lack of deep understanding on the failure mechanism of NM has seriously hindered its application,especially under the harsh condition of high-voltage without sacrifices of reversible ***,singlecrystal liNi_(0.8)Mn_(0.2)O_(2) is selected and compared with traditional liNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM),mainly focusing on the failure mechanism of Cofree cathode and illuminating the significant effect of Co element on the li/Ni antisite defect and dynamic ***,the presence of high li/Ni antisite defect in NM cathode easily results in the extremely dramatic H2/H3 phase transition,which exacerbates the distortion of the lattice,mechanical strain changes and exhibits poor electrochemical performance,especially under the high cutoff ***,the reaction kinetic of NM is impaired due to the absence of Co element,especially at the single-crystal ***,the negative influence of li/Ni antisite defect is controllable at low current densities,owing to the attenuated ***,Co-free NM can exhibit better safety performance than that of NCM *** findings are beneficial for understanding the fundamental reaction mechanism of single-crystal Ni-rich Co-free cathode materials,providing new insights and great encouragements to design and develop the next generation of liBs with low-cost and high-safety performances.

关键词： li/Ni antisite defect Dynamic characteristic High-voltage Single-crystal Ni-rich Co-free cathodes lithium-ion batteries

Enhancing thermodynamic stability of single-crystal Ni-rich cathode material via a synergistic dual-substitution strategy

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Journal of Energy Chemistry 2024年第1期88卷 428-436,I0010页

作者： jixue Shen Hui li Haoyu Qi Zhan lin Zeheng li Chuanbo Zheng Weitong Du Hao Chen Shanqing Zhang School of Metallurgy Engineering Jiangsu University of Science and TechnologyZhangjiagang 215600JiangsuChina School of Metallurgy and Environment Central South UniversityChangsha 410083HunanChina Guangdong Laboratory of Chemistry and Fine Chemical Industry Jieyang Center Jieyang 515200GuangdongChina Institute of Sustainable Transformation School of Chemical Engineering and Light IndustryGuangdong University of TechnologyGuangzhou 510006GuangdongChina Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology College of Chemical and Biological EngineeringZhejiang UniversityHangzhou 310027ZhejiangChina Centre for Catalysis and Clean Energy School of Environment and ScienceGold Coast CampusGriffith UniversityGold Coast 4222QueenslandAustralia

Nickel(Ni)-rich cathode materials have become promising candidates for the next-generation electrical vehicles due to their high specific ***,the poor thermodynamic stability(including cyclic performance and safety performance or thermal stability)will restrain their wide commercial ***,a single-crystal Ni-rich li Ni_(0.83)Co_(0.12)Mn_(0.05)O_(2) cathode material is synthesized and modified by a dual-substitution strategy in which the high-valence doping element improves the structural stability by forming strong metal–oxygen binding forces,while the low-valence doping element eliminates high li^(+)/Ni^(2+)*** a result,this synergistic dual substitution can effectively suppress H2-H3 phase transition and generation of microcracks,thereby ultimately improving the thermodynamic stability of Ni-rich cathode ***,the dual-doped Ni-rich cathode delivers an extremely high capacity retention of 81%after 250 cycles(***/li+)in coin-type half cells and 87%after 1000 cycles(***/li^(+))in pouch-type full cells at a high temperature of 55℃.More impressively,the dual-doped sample exhibits excellent thermal stability,which demonstrates a higher thermal runaway temperature and a lower calorific *** synergetic effects of this dual-substitution strategy pave a new pathway for addressing the critical challenges of Ni-rich cathode at high temperatures,which will significantly advance the high-energy-density and high-safety cathodes to the subsequent commercialization.

关键词： Ni-rich cathode Single crystalline Dual-substitution strategy High-temperature cathode li-ion batteries

Oxidation behavior of cobalt nanoparticles studied by in situ environmental transmission electron microscopy

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Science Bulletin 2017年第11期62卷 775-778页

作者： Dejiong Zhang Chuanhong Jin Z.Y.li Ze Zhang jixue li State Key Laboratory of Silicon Materials School of Materials Science and EngineeringZhejiang University Nanoscale Physics Research Laboratory School of Physics and AstronomyUniversity of Birmingham

The dynamics of oxidation of cobalt nanoparticles were directly revealed by in situ environmental transmission electron ***,cobalt nanoparticles were oxidized to polycrystalline cobalt monoxide,then to polycrystalline tricobalt tetroxide,in the presence of oxygen with a low partial *** cavities(or voids) were formed during the oxidation,owing to the Kirkendall *** of the oxides growth suggested that the oxidation of cobalt nanoparticles followed a parabolic rate law,which was consistent with diffusion-limited *** situ transmission electron microscopy allowed potential atomic oxidation pathways to be *** outward diffusion of cobalt atoms inside the oxide layer controlled the oxidation,and formed the hollow *** by the electron beam,which destroyed the sealing effect of graphite layer coated on the cobalt surface and resulted in fast oxidation rate,played an important role in activating and promoting the *** findings further our understanding on the microscopic kinetics of metal nanocrystal oxidation and knowledge of energetic electrons promoting oxidation reaction.

关键词： Cobalt Nanoparticle Oxidation dynamics Parabolic rate Environmental transmission electron microscopy (ETEM) Electron irradiation

Atomic-scale mechanism of the θ’’→θ’ phase transformation in Al-Cu alloys

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Journal of Materials Science & Technology 2017年第10期33卷 1159-1164页

作者： Zhenju Shen Qingqing Ding Chunhui liu Jiangwei Wang He Tian jixue li Ze Zhang Center of Electron Microscopy Zhejiang University Hangzhou 310027 China Center for High-Resolution Electron Microscopy College of Materials Science and Engineering Hunan University Changsha 410082 China State Key Laboratory of Silicon Materials Department of Materials Science and Engineering Zhejiang University Hangzhou 310027 China

The phase transformation of θ’’→θ’ in an Al-5.7 Cu alloy was investigated by aberration-corrected scanning transmission electron microscopy, and the tranformation mode of θ’’→θ’ during aging treatment was clarified. In the presence of the θ’ phases, θ’ was found to be formed by in-situ transformation fromθ’’ with the same plate shape, size and broad faces. The transformation starts from multiple sites within the θ’ precipitate and the whole θ’ phase finally forms as the preferential θ’ sections grow and connect with each other. Antiphase domain boundaries are also found in some θ’ precipitates when the disregistry exists between different θ’ sections.

关键词： Al-Cu alloy θ’ phase Phase transformation Antiphase domains High-angle annular dark field(HAADF)

In situ observation of sublimation-enhanced magnesium oxidation at elevated temperature

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Nano Research 2016年第9期9卷 2796-2802页

作者： Zijiao Zhang Xiaoqian Fu Minmin Mao Qian Yu Scott X.Mao jixue li Ze Zhang Center of Electron Microscopy and State Key Laboratory of Silicon Materials Department of Materials Science & EngineeringZhejiang UniversityHangzhou 310027China Department of Mechanical Engineering & Materials Science University of PittsburghPittsburghPA 15261USA

Oxidation plays a tremendous role in the long-term performance of metals. As an important lightweight metal for industrial applications, magnesium suffers from its high reactivity with oxygen and increased evaporation at high temperatures. To understand the oxidation mechanism of magnesium at elevated temperatures, in situ environmental transmission electron microscopy (E-TEM) was performed on magnesium nanoparticles. At a relatively low temperature, the growth of a MgO lamellae via the outward diffusion of bulk magnesium atoms dominated the oxidation process. In contrast, a sublimation-enhanced oxidation via gas phase reaction occurred at 200 °C, leading to the growth of MgO dendrites over the particle that finally leads to the degradation of the magnesium structure. This study provides a direct observation and model of the oxidation mechanism of a direct gas–gas reaction that improves our understanding of the oxidation mechanism at elevated temperatures. [Figure not available: see fulltext.] © 2016, Tsinghua University Press and Springer-Verlag Berlin Heidelberg.

关键词： oxidation magnesium sublimation nanoparticle

Deriving phosphorus atomic chains from few-layer black phosphorus

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Nano Research 2017年第7期10卷 2519-2526页

作者： Zhangru Xiao Jingsi Qiao Wanglin Lu Guojun Ye Xianhui Chen Ze Zhang Wei Ji jixue li Chuanhong Jin State Key Laboratory of Silicon Materials School of Materials Science and Engineering Zhejiang University Hangzhou 310027 China Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-nano Devices Renmin University ot China Beijing 100872 China Key Laboratory of Strongly-coupled Quantum Matter Physics Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics University of Science and Technology of China Hefei 230026 China Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing 210093 China

Phosphorus atomic chains, the narrowest nanostructures of black phosphorus （BP）, are highly relevant to the in-depth development of BP-based one-dimensional （1D） nano-electronics components. In this study, we report a top-down route for the preparation of phosphorus atomic chains via electron beam sculpturing inside a transmission electron microscope （TEM）. The growth and dynamics （i.e., rupture and edge migration） of 1D phosphorus chains are experimentally captured for the first time. Furthermore, the dynamic behavior and associated energetics of the as-formed phosphorus chains are further investigated by density functional theory （DFT） calculations. It is hoped that these 1D BP structures will serve as a novel platform and inspire further exploration of the versatile properties of BP.

关键词： black phosphorus one-dimensionalatomic chain density functional theory

High-performance self-organized Si nanocomposite anode for lithium-ion batteries

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Journal of Energy Chemistry 2014年第3期23卷 291-300页

作者： Xiuyun Zhao Dingguo Xia lin Gu Juncheng Yue Biao li Hang Wei Huijun Yan Ruqiang Zou Yingxia Wang Xiayan Wang Ze Zhang jixue li College of Engineering Peking University Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences College of Chemistry and Molecular Peking University College of Environmental and Energy Engineering Beijing University of Technology Center of Electron Microscopy Zhejiang University

Silicon is being investigated extensively as an anodic material for next-generation lithium ion batteries for portable energy storage and electric ***,the large changes in volume during cycling lead to the breakdown of the conductive network in Si anodes and the formation of an unstable solid-electrolyte interface,resulting in capacity ***,we demonstrate nanoparticles with a Si@Mn22.6Si5.4C4@C double-shell structure and the formation of self-organized Si-Mn-C nanocomposite anodes during the lithiation/delithiation *** anode consists of amorphous Si particles less than 10 nm in diameter and separated by an interconnected conductive/buffer network,which exhibits excellent charge transfer kinetics and charge/discharge performances.A stable specific capacity of 1100 mAh·g-1 at 100 mA·g-1 and a coulombic efficiency of 99.2%after 30 cycles are ***,a rate capacity of 343 mAh·g-1 and a coulombic efficiency of 99.4%at 12000 mA·g-1 are also *** to its simplicity and applicability,this strategy for improving electrode performance paves a way for the development of high-performance Si-based anodic materials for lithium ion batteries.

关键词： cycling performance self-organized Si nanocomposite anode lithium ion batteries

Direct observation of Pt nanocrystal coalescence induced by electron-excitation-enhanced van der Waals interactions

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Nano Research 2014年第3期7卷 308-314页

作者： Ying Jiang Yong Wang Yu Yang Zhang Zhengfei Zhang Wentao Yuan Chenghua Sun Xiao Wei Casey N. Brodsky Chia-Kuang Tsung jixue li Xiaofeng Zhang Scott X. Mao Shengbai Zhang Ze Zhang Center of Electron Microscopy and State Key Laboratory of Silicon Materials Department of Materials Science and Engineering Zhejiang University Hangzhou 310027 China Department of Physics Applied Physics and Astronomy Rensselaer Polytechnic Institute Troy New York 12180 USA Centre for Computational Molecular Science Australian Institute for Bioengineering and Nanotechnology University of Queensland St Lucia QLD 4072 Australia Department of Chemistry Boston College Chestnut Hill MA 02467 USA Hitachi High Technologies America Pleasanton CA 94588 USA Department of Mechanical Engineering and Materials Science University of Pittsburgh Pittsburgh PA 15261 USA

Nanocrystal coalescence has attracted paramount attention in nanostructure fabrication in the past decades. Tremendous endeavor and progress have been made in understanding its mechanisms, benefiting from the development of transmission electron microscopy. However, many mechanisms still remain unclear, especially for nanocrystals that lack a permanent dipole moment standing on a solid substrate. Here, we report an in situ coalescence of Pt nanocrystals on an amorphous carbon substrate induced by electron-excitation- enhanced van der Waals interactions studied by transmission electron microscopy and first principles calculations. It is found that the electron-beam-induced excitation can significantly enhance the van der Waals interaction between Pt nanocrystals and reduce the binding energy between Pt nanocrystals and the carbon substrate, both of which promote the coalescence. This work extends our understanding of the nanocrystal coalescence observed in a transmission electron microscope and sheds light on a potential pathway toward practical electron- beam-controlled nanofabrication.

关键词： Pt nanocrystals coalescence electron excitation van der Waals interactions

中国信息系统理论研究现状和发展趋势：2000—2009

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情报学报 2011年第11期30卷 1209-1218页

作者：李东黎璨李继学北京大学光华管理学院北京100871

在过去半个世纪中，信息系统（informationsystems，IS）研究所涉及的范围不断扩张，研究主题也不断受到越来越多IS学者的关注。本文在前人研究的基础上，开发了新的Is研究主题的分类体系。通过对2000—2009年发表在我国18种与IS相关的... 详细信息

在过去半个世纪中，信息系统（informationsystems，IS）研究所涉及的范围不断扩张，研究主题也不断受到越来越多IS学者的关注。本文在前人研究的基础上，开发了新的Is研究主题的分类体系。通过对2000—2009年发表在我国18种与IS相关的学术期刊上的765篇论文进行实证分析，发现国内IS的研究主题比较广泛，涉及信息系统技术、组织、社会等多方面；发现“特定的信息系统”、“方法和技术”、“组织学习和知识管理”、“电子商务”、“电子政务”等8个热点主题，并对它们的发展趋势进行了分析。这些发现可以对IS学者了解中国IS领域的特点以及今后的研究方向选择等提供一些有用的启示。

关键词：信息系统学科研究主题理论研究