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Low thermal conductivity of dense(TiZrHfVNbTa)C_(x) high-entropy carbides by tailoring carbon stoichiometry

Journal of advanced Ceramics 2023年第1期12卷 49-58页

作者： Lei CHEN Wen ZHANG Wenyu LU Boxin WEI Sijia HUO Yujin WANG Yu ZHOU Institute for Advanced Ceramics School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150001China Key Laboratory of Advanced Structural–Functional Integration Materials&Green Manufacturing Technology Harbin Institute of TechnologyHarbin 150001China School of Materials Science and Chemical Engineering Harbin University of Science and TechnologyHarbin 150001China

Transition metal carbides are promising candidates for thermal protection materials due to their high melting points and excellent mechanical ***,the relatively high thermal conductivity is still a major obstacle to its application in an ultra-high-temperature insulation *** this work,the low thermal conductivity of dense(TiZrHfVNbTa)Cx(x=0.6-1)high-entropy carbides has been realized by adjusting the carbon *** thermal conductivity gradually decreases from 10.6 W·m^(−1)·K^(−1) at room temperature to 6.4 W·m^(−1)·K^(−1) with carbon vacancies *** to enhanced scattering of phonons and electrons by the carbon vacancies,nearly full-dense(97.9%)(TiZrHfVNbTa)C_(0.6) possesses low thermal conductivity of 6.4 W·m^(−1)·K^(−1),thermal diffusivity of 2.3 mm^(2)·s^(−1),as well as electrical resistivity of 165.5μΩ·*** thermal conductivity of(TiZrHfVNbTa)C_(0.6) is lower than that of other quaternary and quinary high-entropy carbide ceramics,even if taking the difference of porosity into account in some cases,which is mainly attributed to compositional complexity and carbon *** provides a promising route to reduce the thermal conductivity of high-entropy carbides by increasing the number of metallic elements and carbon vacancies.

关键词： high-entropy carbides thermal conductivity compositional complexity carbon vacancies

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Enhanced Intertwined Spin and Charge Orders in the t–J Model in a Small J Case

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Chinese Physics Letters 2023年第3期40卷 41-44页

作者：张渝梅佳伟陈伟强 Department of Physics and Shenzhen Institute for Quantum Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices Southern University of Science and TechnologyShenzhen 518055China

The one-band t–J model captures strong correlations in cuprate high-temperature *** accounts for the various intertwined spin and charge orders,and the superconductivity in the phase *** see the correlation effect on the intertwined orders,we implement the density matrix renormalization group method to simulate the t–J model in a small J case with t/J=10,which is in a deeper Mott region than that with t/J?3 in cuprate superconducting *** examine the results on a six-leg lattice with both the nearest and next-nearest-neighbor hoppings and antiferromagnetic coupling,and find the absence of superconductivity and enhanced intertwined spin and charge orders in the phase *** the stripe phases,we find a new SDW+CDW phase in which the spin modulation is a(π,π)antiferromagnetism,while the wavelength of the charge modulation is shorter than that of the stripe *** results suggest the enhanced intertwined orders and suppressed superconductivity in the deep Mott region.

关键词： compounds orders superconductivity

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A bi-functional catalyst strategy to selectively regulate sulfur redox kinetics in lithium-sulfur batteries

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Journal of Materials science & technology 2024年第6期173卷 54-62页

作者： Yanan Liu Xiaoxiao Huang Honglei Zhang Guangyu Qin Xiaoshuang Wang Meixiu Song Hongbo Liang Jingzhe Hong Yudong Huang State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China MIIT Key Laboratory of Advanced Structural-Functional Integration Materials&Green Manufacturing Technology Harbin Institute of TechnologyHarbin 150001China School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China School of Chemistry and Chemical Engineering Harbin Institute of TechnologyHarbin 150001China

Designing electrochemical catalysts has become a research hotspot due to their accelerating the polysulfide conversion of the sulfur cathode to inhibit the“shuttle effect”in lithium-sulfur ***,it is still a great challenge to design the heterogeneous selective electrochemical catalyst for inhibiting the“shuttle effect”.Herein,nickel cobalt phosphide and cobalt phosphide as the heterogeneous catalyst active sites embedded in the nitrogen-doped hollow carbon nanocages(NiCoP@CoP/NC)are reported,used for multi-step and multi-phase sulfur electrode reaction,and it is found that metal-sulfur d-p hybridization can effectively indicate the intrinsic catalytic activity of metal *** of labor and cooperation of the bi-active NiCoP@CoP as heterogeneous catalysts propel the stepwise polysulfide *** and CoP sites preferentially accelerate the long-chain polysulfide conversion reaction(S_(8)■LiPSs)and the short-chain polysulfide conversion reactions(LiPSs■Li_(2)S),***,the hollow and porous N-doped carbon structure can successfully suppress the volume effect and improve the conductivity of the sulfur *** unique design can obtain an effective inhibition of the shuttle effect and rapid electrode *** a result,Li-S batteries demonstrate a high initial capacity of 1063 mAh g^(-1) and a low-capacity decay of 0.04% per cycle within 1000 *** work provides a feasible idea for the design of host materials in Li-S batteries.

关键词： Shuttle effect d-p hybridization Heterogeneous catalysts Stepwise polysulfide conversion

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Crystalline@amorphous core-shell structure of WO3@WO_(3-x)S_(x) established via doping strategy for enhancing magnesium ions storage performance

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Journal of Magnesium and Alloys 2025年第3期13卷 1353-1363页

作者： Shiqi Ding Yuxin Tian Jiankang Chen Guofeng Wang Bing Sun He Lv Lei Wang Guicun Li Alan Meng Zhenjiang Li College of Materials Science and Engineering Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life ScienceMOEShandong Key Laboratory of Biochemical AnalysisCollege of Chemistry and Molecular EngineeringQingdao University of Science and TechnologyQingdao 266042ShandongPR China Qingdao Engineering Research Center for New Metallic Functional Materials Characteristic Laboratory of Advanced Metal Functional Materials and Processing in Universities of ShandongQingdao Binhai UniversityQingdao 266555ShandongPR China

Designing cathode possessing crystalline@amorphous core-shell structure with both active core and shell is a meaningful work for resolving the low speciﬁc capacity,unstable cycling performance and sluggish reaction kinetics issues of rechargeable magnesium batteries(RMBs)by providing more active sites as well as releasing inner stress during ***,WO_(3)@WO_(3-x)S_(x) owning crystalline@amorphous core-shell structure containing both active core and active shell is constructed successfully by introducing S into metastable WO3 structure under temperatureﬁeld *** such structure,amorphous shell would provide continuous Mg^(2+)diffusion channels due to its isotropy property for most Mg^(2+)migrating rapidly to interface and then adsorb at ions reservoir formed by interfacial electricﬁeld for increasing speciﬁc *** also makes security for stable structure of WO_(3)@WO_(3-x)S_(x) by alleviating volume expansion of crystalline core WO_(3) during cycling to prolong cycling ***,“softer”ions S^(2-)would weaken interaction between hard acid Mg^(2+) and ionic lattice to enhance Mg^(2+)storage ***,WO_(3)@WO_(3-x)S_(x) delivers the superior cycling performance(1000 cycles with 83.3%),rate capability(88.5 mAh g^(-1) at 1000 mA g^(-1))and speciﬁc capacity(about 150 mAh g^(-1) at 50 mA g^(-1)),which is near 2 times higher than that of *** is believed that the crystalline@amorphous core-shell structure with both active core and shell designing via doping strategy is enlightening for the development of high-performance RMBs,and such design can be extended to other energy storage devices for better electrochemical performance.

关键词： Doping Sulfuration Crystalline@amorphous core-shell structure WO_(3) Rechargeable magnesium batteries

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Integration of urchin-like MnCo_(2)O_(4)@C core–shell nanowire arrays within porous copper current collector for superior performance Li-ion battery anodes

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Rare Metals 2024年第2期43卷 599-611页

作者： Xue-Ru Zhang Qiong Wu Yong Zhang Xi-Fei Li Ting Xie Yu-Cheng Wu Instrumental Analysis Center Hefei University of TechnologyHefei230009China Key Laboratory of Advanced Functional Materials and Devices of Anhui Province Hefei230009China School of Materials Science and Engineering Hefei University of TechnologyHefei230009China Institute of Advanced Electrochemical Energy Xi’an University of TechnologyXi’an710048China

Spinel MnCo_(2)O_(4) is a promising energy storage candidate as anode materials in lithium-ion batteries owing to synergistic effects of two intrinsic solid-state redox ***,low conductivity,poor rate capacity and rapid capacity fading have seriously impaired its practical *** overcome the inferiorities,urchin-like MnCo_(2)O_(4)@C core–shell nanowire arrays have been fabricated directly within a porous copper current collector via a facile hydrothermal method followed by a chemical vapor deposition carbonization *** a typical nanowire,the core is composed of interconnected MnCo_(2)O_(4)nanoparticles and the shell shows as a thin amorphous carbon *** integrated MnCo_(2)O_(4)@C/Cu structure could act as working anodes without using additives or polymer *** MnCo_(2)O_(4)@C/Cu possesses slightly longer Li-ion insertion/desertion pathway than that of MnCo_(2)O_(4)/Cu,the carbon shell could effectively prevent the pulverization of MnCo_(2)O_(4) and lower down charge transfer resistance and actively participate in Li-ion *** rearrangement of carbon atoms during lithiation/delithiation cycling could inhibit the formation of passive solid electrolyte interphase *** a result,the MnCo_(2)O_(4)@C/Cu electrode presents superior rate capacity(600 mAh·g^(−1) at 1 A·g^(−1)) and better stability(797 mAh·g^(−1) after 200 cycles at 100 mA·g^(−1)).The excellent reversible Li ion storage capacity,cycling stability and rate capacity endow MnCo_(2)O_(4)@C/Cu great potential as stable and high output integrated anode materials in Li-ion batteries.

关键词： MnCo_(2)O_(4)@C Urchin-like nanowire arrays Core-shell Integrated anode materials Lithium-ion batteries

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Difunctional undulating interface optimizes the structure-comprehensive properties of graphene/CuNb composite with analogy-bicontinuous structure

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Journal of Materials science & technology 2024年第28期195卷 227-233页

作者： Siyuan Guo Xiang Zhang Chunsheng Shi Dongdong Zhao Chunnian He Naiqin Zhao School of Materials Science and Engineering and Tianjin Key Laboratory of Composite and Functional Materials Tianjin UniversityTianjin 300350China Key Laboratory of Advanced Ceramics and Machining Technology Ministry of EducationTianjin UniversityTianjin 300350China

*** To mitigate the distressing problem of mutual exclusion between mechanical properties-electrical conductivity(EC)in Cu alloy and meet the multiple requirements on properties,suitable ad-ditive phases with combined extraordinary performance have commonly been utilized to endow Cu matrix composites with comprehensive properties[1-4].Promoting dislocation-phase boundary interactions and interfacial bonding enables markedly altering the strength of composites through phase boundary strengthening and loading transfer.

关键词： composites composite structure

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Spinodal dynamics of metastable glass transition domains in amorphous polymer towards thermomechanically tailorable shape memory effect

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science China(Technological sciences) 2023年第8期66卷 2432-2440页

作者： LIU JingYun LU HaiBao FU Yong-Qing Science and Technology on Advanced Composites in Special Environments Laboratory Harbin Institute of TechnologyHarbin 150080China Faculty of Engineering and Environment Northumbria UniversityNewcastle upon TyneNE18STUK

Glass transition plays a critical role to determine the dynamic behaviors of amorphous shape memory polymers(SMPs).However,the fundamental relationships between shape memory effect(SME)and dynamic glass transition have not been well understood,even though this topic has been studied for *** this study,we apply a mean-square displacement function of Adam-Gibbs(AG)domain size model to explore metastable glass transition between normal glass state and rubbery state of amorphous SMPs,based on both mode-coupling theory and mean-field model.A statistic viscosity equation is formulated to study the dynamic glass transition of metastable AG domains in an amorphous SMP.A dynamically spinodal model is also developed to connect dynamic glass transitions to thermomechanical processes,based on statistic viscosity equation and phase transition ***,using the spinodal models,multiple shape memory behaviors have been predicted for amorphous SMPs with dual-,triple-and quadruple-SMEs,resulted from their different routes of themomechanical ***,the proposed models are verified using the experimental data reported in literature.

关键词： shape memory polymer glass transition dynamics metastable

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Surface engineering of 1D nanocatalysts for value-added selective electrooxidation of organic chemicals

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Nano Research 2024年第3期17卷 1327-1336页

作者： Yongping Yang Chuhao Liu Tinglu Song Mufan Li Zipeng Zhao Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications Experimental Center of Advanced MaterialsSchool of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China Beijing National Laboratory for Molecular Sciences College of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China

Electrolytic water splitting by renewable energy is a technology with great potential for producing hydrogen(H_(2))without carbon emission,but this technical route is hindered by its huge energy(electricity)cost,which is mainly wasted by the anode oxygen evolution reaction(OER)while the value of the anode product(oxygen)is very *** the high-energy-cost OER with a selective organic compound electrooxidation carried out at a relatively lower potential can reduce the electricity cost while producing value-added ***,H_(2) generation coupled with synthesis of value-added organic compounds faces the challenge of low selectivity and slow generation rate of the anodic ***-dimensional(1D)nanocatalysts with a unique morphology,well-defined active sites,and good electron conductivity have shown excellent performance in many electrocatalytic *** rational design and regulation of 1D nanocatalysts through surface engineering can optimize the adsorption energy of intermediate molecules and improve the selectivity of organic electrooxidation ***,we summarized the recent research progress of 1D nanocatalysts applied in different organic electrooxidation reactions and introduced several different fabrication strategies for surface engineering of 1D ***,we focused on the relationship between surface engineering and the selectivity of organic electrooxidation reaction ***,future challenges and development prospects of 1D nanocatalysts in the coupled system consisting of organic electrooxidation and hydrogen evolution reactions are briefly outlined.

关键词： hydrogen generation organic compound electrooxidation one-dimensional(1D)nanocatalysts surface engineering selectivity

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Fabrication of electrical semi-conductive SiCN ceramics by vat photopolymerization

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Journal of Materials science & technology 2023年第34期165卷 123-131页

作者： Siyao Chen Xue Wan Jinping Li Bo Gao Xuliang Chen Songhe Meng Jian Lu National key laboratory of Science and Technology on Advanced Composites in Special Environments Harbin Institute of TechnologyHarbin 150080China Department of Mechanical Engineering City University of Hong KongHong KongSARChina

The emergence of additive manufacturing(AM)enables ceramics to be fabricated with customized geometry,and polymer-derived ceramics(PDCs)has attracted growing attention owing to their irreplaceable *** combination of 3D printing and PDCs endows the resultant ceramics with both precision and ***,AM of ceramics from preceramic polymers is still challenging,and insufficient investigation of functionality also limits the versatility of precursor and its derived ***,we propose a novel paradigm for 3D printing dense silicon carbonitride ceramic and study its electrical semiconducting *** formulated photosensitive precursor inks could achieve self-polymerization and cross-linking under the radiation of UV light(405 nm).The green body with intricate structures is fabricated by digital light processing(DLP).Lightweight(1.79-2.08 g cm^(-3))and low porosity(<5%)amorphous ceramics were obtained after thermal *** of cross-linking,decomposition,and ceramization are monitored and ***,the semi-conducting behaviors of resultant ceramics are identified where the conductivity(10^(-5)-10^(-1)S m^(-1))has a monotonic correspondence with the testing temperatures(25-1000℃).The numerical relationship is fitted by exponential functions,and its conducting mechanism could be interpreted by the band tail hopping(BTH)*** work could provide alternative solutions for the fabrication of PDCs and potentials for sensing applications.

关键词： Additive manufacturing Polymer-derived ceramics Digital light processing Silicon carbonitride Semi-conducting behavior

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Ablation resistance of ZrC coating modified by polymer-derived SiHfOC ceramic microspheres at ultrahigh temperature

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Journal of Materials science & technology 2024年第15期182卷 119-131页

作者： Xuemeng Zhang Yuyu Zhang Lingxiang Guo Bing Liu Yuqi Wang Hongbin Li Hejun Li Jia Sun Shaanxi Key Laboratory of Fiber Reinforced Light Composite Materials State Key Laboratory of Solidification ProcessingNorthwestern Polytechnical UniversityXi’an 710072China China Aerodynamics Research and Development Center Mianyang 621000China Science and Technology on Advanced Ceramic Fibers and Composites Laboratory National University of Defense TechnologyChangsha 410073China

Polymer-derived ceramics(PDCs)method opens up new possibilities for the preparation of novel multi-phase ceramic nanocomposites owing to the molecular design of the precursors at the nanoscale *** the current work,ZrC coatings incorporated with polymer-derived ceramic microspheres(CMS),SiH-fOC_CMS,were deposited to enhance the ablation resistance by supersonic atmosphere plasma *** 10.0 MW·m^(-2) plasma ablation at above 3000℃,the linear ablation rate of ZrC-SiHfOC_CMS coat-ing was reduced to 0.20μm·s^(-1),62%lower than that of the pristine ZrC *** improvement was ascribed to the presentence of viscous SiO_(2)/HfO_(2) molten mixed phase,rather than HfSiO4,which can ef-fectively seal pinholes and ***,the in-situ generated crystalline SiO_(2) had a lower oxygen diffusion rate than amorphous SiO_(2),meanwhile,m-HfO_(2) could improve the stability of SiO_(2) glassy film,thus further enhancing the ablation resistance.

关键词： ZrC Polymer-derived ceramics(PDCs) Carbon/Carbon composites Plasma spraying Plasma ablation

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