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Porous polyimide-based phase change materials with enhanced mechanical properties, thermal conductivity, and thermal shock resistance through precisely designed triple-functional layers

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中国科学:技术科学英文版 2023年第9期66卷 2716-2724页

作者： JIANG Miao XIAO Chao DING Xin WANG YanYan ZHANG Xian DU YuHang LI XiaoFei ZHENG Kang LIU XiangLan CHEN Lin TIAN XingYou Key Lab of Photovoltaic and Energy Conservation Materials Institute of Solid State PhysicsHFIPSChinese Academy of SciencesHefei 230031China Science Island Branch University of Science and Technology of ChinaHefei 230026China Lu’an Branch Anhui Institute of Innovation for Industrial TechnologyLu’an 237000China

Numerous scenarios of direct contact between electronic components and skin appear in wearable electronic devices. As the “second skin” that lies next to the biological skin of the human body, flexible wearable devices need to be equipped with thermal protection. However, the use of flexible phase change materials(PCMs) for wearable devices remains a challenge due to their low thermal conductivity, weakened mechanical strength, and liquid leakage. Herein, we developed a multilayered polyimide(PI) composite film integrating stable latent heat absorption, high thermal conductivity, and enhanced mechanical strength. This single piece of material achieved more prominent hotspot protection than traditional foams. The in-plane thermal conductivity of the resultant substrate layer is up to 2.655 W/(m K), which provides a fast response and in-plane dissipation for heat flow. The deliberately arranged interlayer of the material significantly improved the tensile strength(37.6 MPa) of the composite film,representing 128.9% greater strength than that of a bilayer film without a dense layer. The top layer with abundant pores provides reversibly latent heat storing and releasing function after being well infiltrated with paraffin wax. The resulting synergistic effect between three functional layers shows superb heat-suppressing performance in the thickness direction in both thermal shockresistant tests and simulation results. Impressively, the maximum temperature drop reached 40.2℃ compared with the pure PI film. The heating time was delayed by 12 s, providing sufficient warning time for human emergency response. This strategy can potentially pave the way for the design and fabrication of multifunctional films for wearable electronics in thermal protection applications.

关键词： foams layered structures thermal properties thermal analysis

Thermoelectric performance enhancement by manipulation of Sr/Ti doping in two sublayers of Ca_(3)Co_(4)O_(9)

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Journal of Advanced Ceramics 2020年第6期9卷 769-781页

作者： Li ZHANG Yichen LIU Thiam Teck TAN Yi LIU Jian ZHENG Yanling YANG Xiaojiang HOU Lei FENG Guoquan SUO Xiaohui YE Sean LI Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials School of Materials Science and EngineeringShaanxi University of Science&TechnologyXi’an 710021China UNSW Materials and Manufacturing Futures Institute School of Material Science and EngineeringThe University of New South WalesKensingtonNew South Wales2052Australia

Thermoelectric(TE)performance of Ca_(3)Co_(4)O_(9)(CCO)has been investigated extensively via a doping strategy in the past ***,the doping sites of different sublayers in CCO and their contributions to the TE performance remain unrevealed because of its strong correlated electronic *** this work,Sr and Ti are chosen to realize doping at the[Ca_(2)CoO_(3)]and[CoO_(2)]sublayers in *** was found that figure of merit(ZT)at 957 K of Ti-doped CCO was improved 30% than that of undoped CCO whereas 1 at% Sr doping brought about a 150% increase in ZT as compared to undoped *** significant increase in electronic conductivity and the Seebeck coefficient are attributed to the enhanced carrier concentration and spin-entropy of Co^(4+) originating from the Sr doping effects in[Ca_(2)CoO_(3)]sublayer,which are evidenced by the scanning electron microscope(SEM),Raman,Hall,and X-ray photoelectron spectroscopy(XPS)***,the reduced thermal conductivity is attributed to the improved phonon scattering from heavier Sr doped Ca site in[Ca_(2)CoO_(3)]*** findings demonstrate that doping at Ca sites of[Ca_(2)CoO_(3)]layer is a feasible pathway to boost TE performance of CCO material through promoting the electronic conductivity and the Seebeck coefficient,and reducing the thermal conductivity *** work provides a deep understanding of the current limited ZT enhancement on CCO material and provides an approach to enhance the TE performance of other layered structure materials.

关键词： layered structures manipulation doping sites Ca_(3)Co_(4)O_(9)(CCO) spin-entropy thermoelectric performance

Asymmetry in interface and bending property of Al/Cu/Al bimetallic laminates

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Rare Metals 2014年第5期33卷 556-562页

作者： Xiao-Bing Li Guo-Yin Zu Ping Wang School of Materials and Metallurgy Northeastern University

This work was aimed to study the interfacial microstructures and three-point bending properties of Al/Cu/Al bimetallic laminates produced by the asymmetrical roll bonding and annealing. It is found that the microstructure and bonding strength of the Al/Cu interface are different with those of the Cu/Al interface. The interfacial microstructure of Cu/Al interface is improved due to the large interfacial plastic deformation caused by the different rotation speeds of roll in the asymmetrical roll bonding process. The bonding strength between Al and Cu layer can be enhanced by the moderate atomic diffusion, but is dramatically depressed by the formation of intermetallic compounds in the *** bending strength of bimetallic laminates is enhanced when the Cu/Al interface is loaded in tension because of the improvement of stress transition and damping by the Cu/Al interface during the three-point bending deformation. The bending fracture reveals that the interfacial cracks can be inhibited from the restricted stress concentration in the improved Cu/Al interface.

关键词： layered structures Bending test Interface Shear deformation

THE EFFECT OF BILINEAR BEHAVIOUR ON THE DIRECTION AND MAGNITUDE OF THE PEELING MOMENT IN A BI-MATERIAL BEAM

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Acta Mechanica Solida Sinica 2011年第6期24卷 506-509页

作者： Ugur Gven Yildiz Technical University Department of Mechanical Engineering

In this work a bi-material beam exhibiting partly bilinear behaviour under a uniform temperature change is analyzed. The essence of solution is based on the approach of Timoshenko＇s mechanics of materials, The main aim of the present analysis is to understand the effect of the bilinear behaviour on the peeling moment. This theoretical mechanics model mentioned here can give us useful insights to improve the resistance against the delamination.

关键词： peeling moment layered structures interface thermo mechanical delamination

Fabrication of High-purity Ternary Carbide Ti_3AlC_2 by Spark Plasma Sintering(SPS)Technique

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Journal of Wuhan University of Technology(Materials Science) 2008年第2期23卷 177-180页

作者： SONG Jinghong YANG Haitao The Centre for Materials Research and Analysis Wuhan University of Technology Wuhan 430074 China Shenzhen University Shenzhen Key Lab of Special Functional MaterialsShenzhen 518060 China

The effect of silicon on synthesis of Ti3AlC2 by spark plasma sintering （SPS） from TiC/Ti/Al powders was investigated. X-ray diffraction （XRD） and scanning electron microscope （SEM） were used for phase identification and microstructure evaluation. The results show that addition of silicon can considerably accelerate the synthesis reaction of Ti3AlC2 and fully dense, essentially single-phase （purity 〉98%） polycrystalline Ti3AlC2 could be successfully obtained by sintering 2TiC/lTi/lAl/0.2Si powders at 1 200- 1 250 ℃ under a pressure of 30 MPa. SEM photographs show that the obtained Ti3AlC2 samples from mixtures powders are in plane-shape with a size of about 2-5 μm and 10-25 μm in the thickness dimension and elongated dimension, respectively.

关键词： Ti3AlC2 ceramics carbides microstructure layered structures

Spinel/Post-spinel engineering on layered oxide cathodes for sodium-ion batteries

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eScience 2021年第1期1卷 13-27页

作者： Yan-Fang Zhu Yao Xiao Shi-Xue Dou Yong-Mook Kang Shu-Lei Chou Institute for Carbon Neutralization College of Chemistry and Materials EngineeringWenzhou UniversityWenzhouZhejiang 325035China Australian Institute for Innovative Materials Institute for Superconducting and Electronic MaterialsUniversity of WollongongInnovation CampusSquires WayNorth WollongongNSW 2522Australia Department of Materials Science and Engineering Korea UniversitySeoul 02841Republic of Korea KU-KIST Graduate School of Converging Science and Technology Korea UniversitySeoul 02841Republic of Korea

Sodium-ion batteries(SIBs)have attracted much scientific interest for use in large-scale energy storage systems because sodium is cheaper than ***,the large radius of Na^(+)and barriers to Na^(+)transport result in sluggish kinetics and complicated structural distortion,leading to unsatisfactory rate capability and poor cycling *** therefore is essential to develop an electrode with enhanced kinetics and a stable structure during cycling to improve SIB *** the various layered oxide cathodes,those with a spinel-like structure could play an important role in boosting electron transport because of their excellent intrinsic conductivity,including by coordinating with Na^(+)insertion/***,thanks to the inherent high stability of the spinel-like phase,it could function as a stabilizer for host cathode *** review summarizes recent advances in spinel engineering on layered oxide cathodes to boost Na^(+)transport kinetics and provide structural stability to achieve high-performance SIBs,focusing particularly on post-spinel structures,layered oxide integrated spinel-like structures,and spinel *** insights proposed in this review will be useful for guiding rational structural engineering and design to drive the development of new materials and chemistries in Na-based electrode materials.

关键词： Sodium-ion batteries Cathode materials layered structures Spinel engineering Electrochemistry

Analysis of the vibration of film bulk acoustic wave resonators based on Mindlin plate theory

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Analysis of the vibration of film bulk acoustic wave resonat...

Influence of thermal conditions on the electrocaloric effect in a multilayer capacitor based on doped BaTiO_(3)

2011年全国压电和声波理论及器件应用研讨会

作者： De-Jin Huang~* Ji WANG School of Mechanical Engineering & Mechanics,Ningbo University,Ningbo 315211

＜正＞Acoustic wave devices,such as Film Bulk Acoustic wave Resonators（FBAR）,crystal resonators and so on,are usually constructed as layered *** on these devices have been traditionally considered as mass addition t... 详细信息

关键词： FBAR layered structures Mindlin plate theory Analytical solution

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Journal of Advanced Dielectrics 2017年第6期7卷 48-56页

作者： V.S.Bondarev I.N.Flerov M.V.Gorev E.I.Pogoreltsev M.S.Molokeev E.A.Mikhaleva A.V.Shabanov A.V.Es’kov Kirensky Institute of Physics Federal Research Center KSC SB RASKrasnoyarsk 660036Russia Siberian Federal University Krasnoyarsk 660074Russia International Laboratory“Materials and structures for Electro-and Magnetocaloric Energy Conversion” ITMO UniversitySt.Petersburg 197101Russia

We present the results of studies of thermal expansion,heat capacity,permittivity,polarization and the influence of different thermal conditions on the intensive electrocaloric ffect(ECE),△T_(AD),in a commercial multilayer capacitor based on doped BaTiO_(3).Investigations in a wide temperature range revealed one anomaly in the behavior of the physical properties at about 290 K characteristic for the *** measurements showed a high reversibility of ECE under equilibrium thermal *** agreement was found between the values of△T_(AD) determined by direct and indirect measurements at the electric field up to 15.4 kV/***-isothermal conditions lead,firstly,to decrease of large△T_(AD)≈0.94 K obtained in adiabatic conditions under E=308 kV/cm to 0.87 K,and,secondly,the appearance of a difference between the values of △T^(ON) and△T^(OFF) determined when the electric field is applied and *** this phenomenon and changing the frequency of the periodic electric field,E=15.4 kV/cm,the efect of cooling was obtained equal to[(OT^(ON)+AT^(OFF))/2]_(max)=-0.032 *** results obtained are useful for further development of the electrocaloric refrigeration technique without thermal switches.

关键词： Electrocaloric effect ferroelectrics layered structures nonequilibrium conditions phase transitions