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Nano Research 2023年第1期16卷 513-520页

作者： Qingmeng Gan Ning Qin Zhiqiang Li Shuai Gu Kemeng Liao Kaili Zhang Li Lu Zhenghe Xu Zhouguang Lu Department of Materials Science and Engineering Shenzhen Key Laboratory of Interfacial Science and Engineering of MaterialsSouthern University of Science and TechnologyShenzhen 518055China Department of Mechanical Engineering National University of Singapore117575Singapore Department of Mechanical Engineering City University of Hong Kong83 Tat Chee AvenueHong Kong 999077China

Nickel-rich layered oxides are attractive cathode for lithium-ion batteries(LIBs)because of the high energy density and low cost.The critical problem is capacity fading caused by the highly reactive metastable phases under voltages of higher than 4.15 V.Herein,we find that facile Ar/H2 plasma treating could produce oxygen vacancies that will readily transform into homogeneous spinel layer(~6 nm)on the LiNi_(0.8)CO_(0.1)Mn_(0.1)O_(2)(NCM811)surface after a few cycles of lithiation/delithiation procedure.Owing to the structural matching between spinel and layered structure,the diffusion of Li ions could remain fast upon cycling.Besides,the spinel layer is electrochemically inert,which guarantees surface stabilization and inhibits the detrimental Phase transition from H2 to H3 at high voltages.Under the protection of the homogeneous spinel layer,the NCM_(811) electrode shows superior capacity retention of 91.2% after 200 cycles at the current density of 100 mA·g^(−1).This work proposes a novel strategy of surface reconstruction to stabilize nickel-rich layered oxide materials for LIBs.

关键词： lithium-ion batteries nickel-rich cathode surface spinel reconstruction Phase transition superior stability

Enhanced Phase transition in Poly(ethylene glycol) Grafted Butene-1 Copolymers

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Chinese Journal of Polymer Science 2023年第3期41卷 414-421,I0008页

作者： Ya-Hui Lou Wei Li Chun-Jing Qv Zhe Ma Tianjin Key Laboratory of Composite and Functional Materials and School of Materials Science and EngineeringTianjin UniversityTianjin 300072China

In the present work,a series of poly(ethylene glycol) grafted polybutene-1 copolymers(PB-g-PEG) were designed and successfully synthesized with reaction intermediate method,of which the branch densities and length could be tuned independently.The branch density varied from 0.39 mol% to 1.23 mol% and the branch length was tuned by employing PEG number-averaged molecular weight(Mn) from 350 Da to 750 Da and 1000 Da.The non-isothermal crystallization and Phase transition behaviors of these butene-1 copolymers with varying branches were systematically explored by differential scanning calorimeter.The results first showed that compared with the linear polybutene-1 homopolymer,presence of steric 4-[4-(trimethylsilylalkynyl)-phenyl]-1-butene(TMS) groups suppressed crystallization and Phase transition of copolymers.Interestingly,the introduction of long poly(ethylene glycol)(PEG) branches with M_(n)=350-1000 Da not only elevated the peak temperature of the non-isothermal crystallization but also enhanced the Ⅱ-Ⅰ Phase transition,with respect to copolymers with TMS groups.Furthermore,the quantitative correlations between Phase transition kinetics with the branch parameters(density and length) were explored.It was found that the Phase transition presents a non-monotonic trend with increasing branch density and branch length.In this case,the optimal branch density and length obtained were 0.77 mol% and 750 Da,respectively.Employing the small angle X-ray scattering and transmission electron microscopy,a direct correlation between the Phase transition kinetics and the long periodicity of separated phase was obtained,which may be due to the increased internal stress and facilitated stress transport.

关键词： Polybutene-1 copolymer Crystallization kinetics Phase transition phase separation

Fast Scan mode of scanning electrochemical microscopy:In-situ characterization of Phase transition and mapping the hydrogen evolution activity for MoS_(2)

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Nano Research 2023年第7期16卷 10011-10017页

作者： Zhenyu Wang Tong Sun Changan HuangFu Sisi Jiang Chaoqun Gu Liying Jiao Zonghua Wang College of Chemistry and Chemical Engineering College of Materials Science and EngineeringShandong Sino-Japanese Center for Collaborative Research of Carbon NanomaterialsInstrumental Analysis Center of Qingdao UniversityQingdao UniversityQingdao 266071China Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education Department of ChemistryTsinghua UniversityBeijing 100084China

Scanning electrochemical microscopy(SECM)is an attractive technology to in-situ characterize the structural evolution and catalytic performance for various electrocatalysts.However,spatial and temporal resolution coupling are still the obstacles that limit its wide applications.Herein,a new operation mode,Fast Scan mode,was developed by improving the dual-pass scan mode,designing novel hardware structure,and employing thermal drift calibration software to achieve a high spatial and temporal resolution simultaneously.The temporal speed can achieve 4 Hz for a high spatial resolution(less than 30 nm)image.This operation mode was employed to dynamically track the Phase transition process of molybdenum disulfide(MoS_(2))over time and characterize the hydrogen evolution reaction(HER)catalytic activity on the edge of semiconducting MoS_(2)quantitatively while minimizing the diffusional broadening effect and total amount of catalytic products generated above the surface.This new approach should be useful for in-situ tracking dynamic electrochemical processes,establishing the structure-activity relationship for structural complex electrocatalysts,and offering a strategy for high-speed scanning with other electrochemical imaging techniques.

关键词： high-speed scanning scanning electrochemical microscopy molybdenum disulfide Phase transition hydrogen evolution reaction

Rate of the Phase transition for a charged anti-de Sitter black hole

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Science China(Physics,Mechanics & Astronomy) 2023年第4期66卷 61-66页

作者： Zhen-Ming Xu Bin Wu Wen-Li Yang School of Physics Northwest UniversityXi'an 710127China Institute of Modern Physics Northwest UniversityXi'an 710127China Shaanxi Key Laboratory for Theoretical Physics Frontiers Xi'an 710127China Peng Huanwu Center for Fundamental Theory Xi'an 710127China

Phase transition is a core content of black hole thermodynamics. This study adopted Kramer’s escape rate method for describing the Brownian motion of particles in an external field to investigate the intensity of the Phase transition between small and large black hole states. Some existing studies mostly focused on the formal analysis of the thermodynamic Phase transition of black holes, but they neglected the detailed description of the Phase transition process. Our results show that the Phase transition between small and large black holes for charged anti-de Sitter(AdS) black holes presents serious asymmetric features, and the overall process is dominated by the transition from a small black hole to a large black hole. This study filled a research gap of a stochastic process analysis on the issue of the first-order Phase transition rate in the Ad S black hole.

关键词： black hole thermodynamics Phase transition thermal potential Kramer’s escape rate

Generalized degradation reliability model considering Phase transition

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Journal of Systems Engineering and Electronics 2022年第3期33卷 748-758页

作者： ZHANG Ao WANG Zhihua WU Qiong LIU Chengrui School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China Institute of Spacecraft System Engineering China Academy of Space TechnologyBeijing 100094China Beijing Institute of Control Engineering Beijing 100094China

Aiming to evaluate the reliability of phase-transition degrading systems,a generalized stochastic degradation model with Phase transition is constructed,and the corresponding analytical reliability function is formulated under the concept of the first hitting time.The phase-varying stochastic property and the phase-varying nonlinearity are considered simultaneously in the proposed model.To capture the phase-varying stochastic pro-perty,a Wiener process is adopted to model the non-monotonous degradation phase,while a Gamma process is utilized to model the monotonous one.In addition,the phase-varying non-linearity is captured by different transformed time scale functions.To facilitate the practical application of the proposed model,identification of phase model type and estimation of model parameters are discussed,and the initial guesses for parameters optimization are also given.Based on the constructed model,two simulation studies are carried out to verify the analytical reliability function and analyze the influence of model misspecification.Finally,a practical case study is conducted for illustration.

关键词： degradation Phase transition reliability stochastic process nonlinearity

Thickness dependence of the crystallization and Phase transition in ZrO_(2)thin films

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Journal of Advanced Ceramics 2023年第4期12卷 822-829页

作者： Yue Guan Jing Zhou Haodong Zhong Weipeng Wang Zhengjun Zhang Feng Luo Shuai Ning School of Materials Science and Engineering Smart Sensing Interdisciplinary Science CenterNankai UniversityTianjin 300350China School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China

Fluorite-structure binary oxides(e.g.,HfO_(2)and ZrO_(2))have attracted increasing interest for a broad range of applications including thermal barrier coatings,high-k dielectrics,and novel ferroelectrics.A crystalline structure plays a crucial role in determining physical and chemical properties.Structure evolution of ZrO_(2)thin films,particularly down to the nanometer scale,has not been thoroughly studied.In this work,we carried out systematic annealing analysis on the ZrO_(2)thin films.Through in-situ high-temperature X-ray diffraction(XRD)characterizations,a thickness dependence of crystallization and Phase transition is observed.Irrespective of the thickness(10-300 nm),the as-prepared amorphous ZrO_(2)thin films are preferentially crystallized into a tetragonal(t)structure(high-temperature phase),which can be preserved down to room temperature(RT)upon anncaling at the corresponding crystallization temperaturc(T).When anncaling at temperaturcs higher than Tc,the transition from t to monoclinic(m;RT phase)will occur,and the quantity of the transition strongly depends on the film thickness.Our work expands the basic understanding of the Phase transition in the ZrO_(2)thin films,and offers a path to the selective control over the phase structure for novel functionalities.

关键词： zirconia crystallization tetragonal(t) monoclinic(m) Phase transition

The Negative Thermal Expansion Property of NdMnO_(3) Based on Pores Effect and Phase transition

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Journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 39-43页

作者：李玉成张扬 ZHANG Muqun DUAN Rong LIU Xiteng Department of Avionics Engineering Aviation Maintenance NCO Academy of Air Force Engineering UniversityXinyang 464000China

A novel negative thermal expansion(NTE) material NdMnO_(3) was synthesized by solid-state method at 1 523 K. The crystal structure, Phase transition, pores effect and negative expansion properties of NdMnO_(3) were investigated by variable temperature X-ray diffraction(XRD), scanning electron microscope(SEM) and variable temperature Raman spectra. The compound exhibits NTE properties in the orderly O' phase crystal structure. When the temperature is from 293 to 759 K, the ceramic NdMnO_(3) shows negative thermal expansion of-4.7×10^(-6)/K. As temperature increases, the ceramic NdMnO_(3) presents NTE property range from 759 to 1 007 K. The average linear expansion coefficient is-18.88×10^(-6)/K. The physical mechanism of NTE is discussed and clarified through experiments.

关键词： negative thermal expansion NdMnO_(3) pores effect Phase transition

Electrochemically induced Phase transition in a nanoflower vanadium tetrasulfide cathode for high-performance zinc-ion batteries

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Journal of Energy Chemistry 2022年第6期31卷 356-362,I0010页

作者： Shizhe Gao Peng Ju Ziquan Liu Lei Zhai Wenbao Liu Xiaoyu Zhang Yanli Zhou Caifu Dong Fuyi Jiang Jianchao Sun School of Environment and Material Engineering Yantai UniversityYantai 264005ShandongChina Key Laboratory of Marine Eco-Environmental Science and Technology Marine Bioresource and Environment Research CenterFirst Institute of OceanographyMinistry of Natural ResourcesQingdao 266061ShandongChina

Aqueous zinc-ion batteries (AZIBs) are promising contenders for large-scale energy storage with the merits of their low cost,high safety,environmental friendliness,and competitive gravimetric energy density.Nevertheless,suitable cathode materials with long cycle life and adequate capacity are still rare.Herein,we report a nanoflower vanadium tetrasulfide/carbon nanotubes (VS_(4)/CNTs) cathode with high Znstorage performance.We propose a Phase transition reaction mechanism from VS_(4)to zinc pyrovanadate in the initial cycles and a reversible intercalation mechanism for Zn^(2+) in zinc pyrovanadate during subsequent cycles.As a result,the cathode delivers a high discharge capacity of 265 mAh g^(-1)at 0.25 A g^(-1)and 182 m Ah g^(-1)at 7 A g^(-1).In addition,the cathode exhibits a long-term cyclability with 93%capacity retention over 1200 cycles at 5 A g^(-1).VS_(4)/CNTs with superior electrochemical performance is a hopeful cathode material in AZIBs.

关键词： Zinc-ion batteries Vanadium tetrasulfide Zinc pyrovanadate Phase transition Reaction mechanism

Dynamic Phase transition behavior of a LiMn_(0.5)Fe_(0.5)PO_(4) olivine cathode material for lithium-ion batteries revealed through in-situ X-ray techniques

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Journal of Energy Chemistry 2022年第8期31卷 452-459,I0012页

作者： Sujeera Pleuksachat Phongsit Krabao Sarawut Pongha Viyada Harnchana Pawinee Klangtakai Wanwisa Limphirat Siriwat Soontaranon Jeffrey Nash Nonglak Meethong Department of Physics Faculty of ScienceKhon Kaen UniversityKhon Kaen 40002Thailand Institute of Nanomaterials Research and Innovation for Energy(IN-RIE) Research Network of NANOTEC-KKU(RNN)Khon Kaen UniversityKhon Kaen 40002Thailand Synchrotron Light Research Institute(SLRI) Nakhon Ratchasima 30000Thailand

LiMn_(0.5)Fe_(0.5)PO_(4) has attracted great interest due to its good electrochemical performance and higher operating voltages.This has led to a greater than 30 percent higher energy density than for commercial Li Fe PO4 olivine cathodes.Understanding the Phase transition behaviors and kinetics of this material will help researchers to design and develop next generation cathodes for Li-ion batteries.In this study,we investigated non-equilibrium Phase transition behaviors in a LiMn_(0.5)Fe_(0.5)PO_(4) cathode material during charge–discharge processes by varying current rates(C-rates)using synchrotron in-situ X-ray techniques.These methods included wide angle X-ray scattering(in-situ WAXS)and X-ray absorption spectroscopy(in-situ XAS).The WAXS spectra indicate that the Phase transition of LiMn_(0.5)Fe_(0.5)PO_(4) material at slow C-rates is induced by a two-phase reaction.In contrast,at a high C-rate(5 C),the formation of an intermediate phase upon discharge is clearly observed.Concurrently,the oxidation numbers of the redox reactions of Fe^(2+)/Fe^(3+)and Mn^(2+)/Mn^(3+)were evaluated using in-situ XAS.This combination of synchrotron in-situ X-ray techniques gives clear insights into the non-equilibrium Phase transition behavior of a LiMn_(0.5)Fe_(0.5)PO_(4) cathode material.This new understanding will be useful for further developments of this highly promising cathode material for practical commercialization.

关键词： LiMn_(0.5)Fe_(0.5)PO_(4) Phase transition In-situ X-ray techniques

Latent Heat of TB18 Titanium Alloy during β to α Phase transition by DSC and First-Principles Methods

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Acta Metallurgica Sinica(English Letters) 2023年第11期36卷 1844-1856页

作者： Yan-Di Jia Shuo Cao Ying-Jie Ma Sen-Sen Huang Feng-Ying Qin Shao-Qiang Li Wei Xiang Qian Wang Qing-Miao Hu Bo Li Jia-Feng Lei Jing Xie Xiang-Hong Liu Rui Yang School of Materials Science and Engineering University of Science and Technology of ChinaShenyang110016China Shi-Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang110016China AVIC The First Aircraft InstituteXi’an710089China Western Superconducting Technologies Co.Ltd.Xi’an710018China China National Erzhong Group Deyang Wanhang Die Forging Co. Ltd.Deyang618000China

The Phase transition of titanium alloys is sensitive to the heat-treatment procedure,accompanied with the latent heat induced by Phase transition.However,the latent heat during Phase transition of titanium alloy has not been systematically studied,which may result in the gap between designed and actual temperature of the sample and affect the final mechanical properties.In this work,DSC(differential scanning calorimetry)and first-principles simulate methods were used to study theβ→αPhase transition process of TB18(Ti–Al-Mo-V-Cr-Nb-Fe system)metastableβtitanium alloy,especially to reveal the influence of the heating rate on latent heat.The ratio of latent heat to endothermic heat of the sample during temperature rising was introduced to interpret the effect of latent heat to actual temperature.The ratio of latent heat to endothermic heat at 1℃/min is about 15 to 20 times higher than that at 10℃/min.The higher ratio indicates that the latent heat of Phase transition has a more significant effect on the temperature,which is related to the temperature range of Phase transition and theαvolume fraction.Compared with the heating rate of 1℃/min,theβ→αPhase transition takes place at higher temperature and the volume fraction ofαis smaller at 10℃/min.Meanwhile,there is a precipitation free zone between grain boundaryαand intragranularαand the distribution ofαlamellae is heterogeneous when the heating rate is 10℃/min.Both of the experimental and theoretical results suggest that the latent heat of Phase transition is the main cause of the temperature fluctuation during heat-treatment process.This work has guiding significance for microstructure optimization affected by temperature,to achieve the desired mechanical properties.

关键词： High-strength titanium alloys Latent heat Phase transition Differential scanning calorimetry(DSC) First-principles calculation