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Symmetry-breaking of LiMn6 hexatomic-ring in grain surface of Li2MnO3

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Journal of Energy Chemistry 2023年第6期81卷 110-117页

作者： Lihang Wang Shu Zhao Boya Wang Haijun Yu institute of advanced Battery materials and Devices Faculty of Materials and Manufacturing Beijing University of Technology Key Laboratory of advanced Functional materials Ministry of Education Beijing University of Technology

LiMn6hexatomic-rings act as functional units in Li-rich layered oxides(LLOs), which determine the capacity, voltage, and structural stability of LLOs. However, the symmetry of the LiMn6hexatomic-ring is always broken, especially in the grain surface of LLOs, which will greatly affect its electrochemical performance. Herein, the symmetry-breaking of LiMn6hexatomic-ring in the grain surface of Li2MnO3was studied, and their effect on charge compensation mechanism and structure evolution behavior was thoroughly investigated. The results show that the electrochemical activity of the symmetry-broken LiMn6hexatomic-ring is higher than that of the unbroken LiMn6, and the former is more favorable for spinelization on the grain surface. Furthermore, the exposure proportion of crystallographic planes with different symmetry-broken LiMn6hexatomic-ring has also been discussed, which can be adjusted by changing the partial pressure of oxygen. The in-depth understanding of the symmetry-breaking of LiMn6hexatomic-ring will provide more targeted strategies for designing high-performance LLOs cathodes for lithium-ion batteries.

关键词： Li-rich layered oxides LiMn6 functional unit Symmetry-breaking Surface structure Density functional theory

Two-Terminal Lithium-Mediated Artificial Synapses with Enhanced Weight Modulation for Feasible Hardware Neural Networks

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Nano-Micro Letters 2023年第5期15卷 236-253页

作者： Ji Hyun Baek Kyung Ju Kwak Seung Ju Kim Jaehyun Kim Jae Young Kim In Hyuk Im Sunyoung Lee Kisuk Kang Ho Won Jang Department of materials Science and Engineering Research Institute of Advanced MaterialsSeoul National UniversitySeoul 08826Republic of Korea advanced institute of Convergence Technology Seoul National UniversitySuwon 16229Korea

Recently,artificial synapses involving an electrochemical reaction of Li-ion have been attributed to have remarkable synaptic properties.Three-terminal synaptic transistors utilizing Li-ion intercalation exhibits reliable synaptic characteristics by exploiting the advantage of nondistributed weight updates owing to stable ion migrations.However,the three-terminal configurations with large and complex structures impede the crossbar array implementation required for hardware neuromorphic systems.Meanwhile,achieving adequate synaptic performances through effective Li-ion intercalation in vertical two-terminal synaptic devices for array integration remains challenging.Here,two-terminal Au/LixCoO_(2)/Pt artificial synapses are proposed with the potential for practical implementation of hardware neural networks.The Au/LixCoO_(2)/Pt devices demonstrated extraordinary neuromorphic behaviors based on a progressive dearth of Li in LixCoO_(2)films.The intercalation and deintercalation of Li-ion inside the films are precisely controlled over the weight control spike,resulting in improved weight control functionality.Various types of synaptic plasticity were imitated and assessed in terms of key factors such as nonlinearity,symmetricity,and dynamic range.Notably,the LixCoO_(2)-based neuromorphic system outperformed three-terminal synaptic transistors in simulations of convolutional neural networks and multilayer perceptrons due to the high linearity and low programming error.These impressive performances suggest the vertical two-terminal Au/LixCoO_(2)/Pt artificial synapses as promising candidates for hardware neural networks.

关键词： Artificial synapse Neuromorphic Li-based Two-terminal Synaptic plasticity

Recent progress in single-atom nanozymes research

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Nano Research 2023年第2期16卷 1878-1889页

作者： Bing Jiang Zhanjun Guo Minmin Liang Experimental Center of advanced materials School of Materials Science&EngineeringBeijing Institute of TechnologyBeijing 100081China

Single-atom nanozyme(SAzyme)is the hot topic of the current nanozyme research.Its intrinsic properties,such as high activity,stability,and low cost,present great substitutes to natural enzymes.Moreover,its fundamental characteristics,i.e.,maximized atom utilizations and well-defined geometric and electronic structures,lead to higher catalytic activities and specificity than traditional nanozymes.SAzymes have been applied in many biomedical areas,such as anti-tumor therapy,biosensing,antibiosis,and anti-oxidation therapy.Here,we will discuss a series of representative examples of SAzymes categorized by their biomedical applications in this review.In the end,we will address the future opportunities and challenges SAzymes facing in their designs and applications.

关键词： single-atom nanozymes natural enzymes enzyme-like activity biomedical applications

界面工程用于提高CoP-Co_(2)P多晶型物在全pH值析氢反应和碱性全解水反应中的电催化性能

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Science China materials 2022年第9期65卷 2433-2444页

作者：陈蕾任金涛袁忠勇 Key Laboratory of advanced Energy materials Chemistry(Ministry of Education) National Institute for Advanced MaterialsSchool of Materials Science and EngineeringNankai UniversityTianjin 300350China

开发具有丰富活性位点和高本征活性的磷化钴催化剂,用于高效且稳定的析氢反应(HER)和析氧反应(OER)具有重要意义.本工作通过精准地控制球形膦酸钴的热还原温度合理地构建了新型的碳包裹的CoP-Co_(2)P多晶型物.独特的多级孔结构和CoP-Co_... 详细信息

开发具有丰富活性位点和高本征活性的磷化钴催化剂,用于高效且稳定的析氢反应(HER)和析氧反应(OER)具有重要意义.本工作通过精准地控制球形膦酸钴的热还原温度合理地构建了新型的碳包裹的CoP-Co_(2)P多晶型物.独特的多级孔结构和CoP-Co_(2)P之间的异质界面不仅提高了活性位点的数量,而且还保证了优异的内在催化活性.所制备的催化剂展现出优异的电催化活性和稳定性(对于全pH值HER(0.5 mol L^(-1) H_(2)SO_(4):81 mV@10 mA cm^(-2);1.0 mol L^(-1) KOH:109 mV@10 mA cm^(-2);1.0 mol L^(-1) PBS:227 mV@10 mA cm^(-2))和碱性OER(1.0 mol L^(-1) KOH:1.53 V@10 mA cm^(-2))).在作为双电极电解槽中全解水反应的双功能电催化剂时,该材料可以在1.60 V的低电压下,1.0 mol L^(-1) KOH电解液中提供10 mA cm^(-2)的电流密度.本文还详细研究了CoP-Co_(2)P多晶型物在催化反应过程中的结构析出.本工作为用于各种电化学技术中的高效且价格合理的金属磷化物的设计和制备提供了一种新的方法.

关键词： cobalt phosphides polymorphs heterointerface hydrogen evolution oxygen evolution

Simultaneous enhancement in mechanical and corrosion properties of Al-Mg-Si alloys using machine learning

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Journal of materials Science & Technology 2023年第36期167卷 1-13页

作者： Xinming Feng Zhilei Wang Lei Jiang Fan Zhao Zhihao Zhang institute for advanced materials and Technology University of Science and Technology BeijingBeijing 100083China Beijing Laboratory of Metallic materials and Processing for Modern Transportation Institute for Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China Key Laboratory for advanced materials Processing(MOE) University of Science and Technology BeijingBeijing 100083China Beijing advanced Innovation Center for materials Genome Engineering Institute for Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China

Al-Mg-Si alloys with high strength and good corrosion resistance are regarded as desirable materials for all-aluminum vehicles.However,the traditional trial-and-error experimental methods are insufficient to address the trade-offbetween strength and corrosion resistance.In this work,a non-dominated sorting genetic machine-learning algorithm(NSGA-II)was employed to optimize the chemical composition,so as to simultaneously improve the strength and corrosion resistance.Three high-performance Al-Mg-Si alloys with low Mg,Si,and Cu contents were successfully developed,where the yield strength(YS),ultimate tensile strength(UTS),and the elongation(δ)reached 375-380 MPa,410-416 MPa,and 13.7%-15.2%,re-spectively.Compared with higher-Cu-content 6013 alloy,the YS and UTS of the present alloys increase by about 60 MPa,and the intergranular corrosion resistance is also significantly improved.Microstruc-ture characterization demonstrated thatβ’’and QP phases introduced a significant synergistic precipita-tion strengthening effect;the dispersoids formed by trace Mn,Cr,Fe,Zr,and Ti contributed dispersion strengthening effect;and the good pitting corrosion resistance is attributed to lower Mg and Si contents.

关键词： Aluminum alloy Machine learning High strength Corrosion resistance

Hydrogen absorption-desorption characteristic of (Ti0.85Zr0.15)1.1Cr1-xMoxMn based alloys with C14 Laves phase

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Progress in Natural Science:materials International 2022年第2期32卷 143-149页

作者： Youhua Yan Zhongyu Li Ying Wu Shaoxiong Zhou Jiangsu JITRI advanced Energy & materials Research institute Co. Ltd. advanced materials Research institute North China Electric Power University

The microstructure and hydrogen absorption-desorption characteristic of(Ti0.85Zr0.15)1.1Cr1-xMoxMn(x = 0.05,0.1,0.15,0.2 at.%) alloys were investigated.The results showed that the corresponding alloys were determined as a single phase of C14-type Laves structure.With the increase of Mo content,the maximum and reversible hydrogen absorption capacity decreased,the slope factor Hf increased.Among the studied alloys,(Ti0.85Zr0.15)1.1Cr0.95Mo0.05Mn had the best overall properties for practical application of hydrogen storage materials.The maximum and reversible hydrogen storage capacity were 1.76 wt% and 1.09 wt%,the slope factor Hfwas 0.51,and its dissociation enthalpy(ΔHd) and entropy change(ΔSd) were 23.1 kJ mol-1H2,93.8 J K-1mol-1 H2at 303 K,respectively.By studying the dissociation pressures of the synthesized metal hydrides,it was found that Mo had a special effect on the dissociation pressure of Ti-Zr-Cr-Mo-Mn alloys.Among the four alloys,(Ti0.85Zr0.15)1.1Cr0.95Mo0.05Mn alloy had the largest hydrogen absorption capacity and the fastest hydrogen desorption rate,which can meet the commercialization demand of hydrogen fuel cell hydrogen supply system.

关键词： Metal hydrides Ti–Zr–Cr–Mo–Mn based Alloys Laves phase Hydrogen storage properties

Controlled crystal orientation of two-dimensional Ruddlesden-Popper halide perovskite films for solar cells

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International Journal of Minerals,Metallurgy and materials 2022年第1期29卷 49-58页

作者： Jiuyao Du Mengqi Zhang Jianjun Tian Beijing advanced Innovation Center for materials Genome Engineering Institute for Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China

Metal halide perovskite solar cells have attracted considerable attention because of their high-power conversion efficiency and costeffective solution-processable fabrication;however,they exhibit poor structural stability.Two-dimensional(2D)Ruddlesden-Popper(RP)perovskites could address the aforementioned issue and present excellent stability because of their hydrophobic organic spacer cations.However,the crystallographic orientation of 2D crystals should be perpendicular to the bottom substrates for charges to transport fast and be collected in solar cells.Moreover,controlling the crystallographic orientation of the 2D RP perovskites prepared by the solution process is difficult.Herein,we reviewed the progress of recent research regarding 2D RP perovskite films with the focus on the crystallographic orientation mechanism and orientation controlling methods.Furthermore,the current issues and prospects of 2D RP perovskites in the photovoltaic field were discussed to elucidate their development and application in the future.

关键词： two-dimensional Ruddlesden-Popper crystallographic orientation perovskite solar cells

Effect of Zr and Ti on isothermal oxidation behavior of Nb–Si based alloys

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Progress in Natural Science:materials International 2022年第2期32卷 226-235页

作者： Ankang Sun Ziqiang Dong Shuang Yang Jintao Shu Yanjie Liu Yi Liu Yongwang Kang Dinggang Wang Jinxia Song materials Genome institute Shanghai University Science and Technology on advanced High Temperature Structural materials Laboratory Beijing Institute of Aeronautical Materials

The isothermal oxidation behavior of 56 Nb-16 Si-(20-x)Ti-3 Cr-3 Al-2 Hf-xZr(x=0,2,5,10 at.%) alloys was investigated at 800℃ and 1250℃,respectively.The results show that increasing the Zr content evidently increased the oxidation rates at 800℃,accompanied by the obvious occurrence of pesting oxidation.The alloys showed alike linear oxidation kinetics at 1250℃.With the increase of Zr content,the adherence and integrity of oxide scales were improved,but the overall oxidation resistance was slightly deteriorated.The observed oxidation behavior may be attributed to the composition variation of Zr and Ti in the alloys.The oxidation mechanism associated with the composition variation is discussed in this study.

关键词： Niobium Silicide Oxidation Zirconium Titanium

Tailorable,Lightweight and Superelastic Liquid Metal Monoliths for Multifunctional Electromagnetic Interference Shielding

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Nano-Micro Letters 2022年第2期14卷 136-150页

作者： Yadong Xu Zhiqiang Lin Krishnamoorthy Rajavel Tao Zhao Pengli Zhu Yougen Hu Rong Sun Ching-Ping Wong Shenzhen institute of advanced Electronic materials Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055People’s Republic of China School of materials Science and Engineering Georgia Institute of TechnologyAtlantaGA 30332USA

Liquid metal(LM)has become an emerging material paradigm in the electromagnetic interference shielding field owing to its excellent electrical conductivity.However,the processing of lightweight bulk LM composites with finite package without leakage is still a great challenge,due to high surface tension and pump-out issues of LM.Here,a novel confined thermal expansion strategy based on expandable microsphere(EM)is proposed to develop a new class of LM-based monoliths with 3D continuous conductive network.The EM/LM monolith(EM/LMm)presents outstanding performance of lightweight like metallic aerogel(0.104 g cm^(-1)),high strength(3.43 MPa),super elasticity(90%strain),as well as excellent tailor ability and recyclability,rely on its unique gas-filled closed-cellular structure and refined LM network.Moreover,the assembled highly conducting EM/LMm exhibits a recorded shielding effectiveness(98.7 dB)over a broad frequency range of 8.2-40 GHz among reported LM-based composites at an ultra-low content of LM,and demonstrates excellent electromagnetic sealing capacity in practical electronics.The ternary EM/LM/Ni monoliths fabricated by the same approach could be promising universal design principles for multifunctional LM composites,and applicable in magnetic responsive actuator.

关键词： Liquid metal Elastic monolith Confined thermal expansion Electromagnetic interference shielding Magnetic actuation