30 July 2021, Volume 52 Issue 7

    

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Focuses & Concerns (The Project of Chongqing Press Fund in 2020)
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  Nanocrystalline diamond film growth by microwave plasma enhanced chemical vapor deposition (MPCVD)

  LIN Chen, LI Yifeng, ZHANG Jinwen

  Journal of Functional Materials. 2021, 52(7): 7001-7005. https://doi.org/10.3969/j.issn.1001-9731.2021.07.001

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  In this paper, five groups of diamond films are deposited under different substrate temperature and ratio of CH₄, H₂ and Ar by MPCVD in order to acquire large area of uniform and continuous nanocrystalline diamond film and explore the effect of temperature and gaseous environment on characteristics of deposited diamond film. ESEM and Raman spectroscopy are used to characterize the quality, morphology, structure and composition of the films. Formation mechanism and influence of technological parameters are analyzed, and further optimizations are proposed.
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  Preparation and properties of double-ring structure hollow silica nanospheres

  LI Fangxian, YANG Yerong, WEI Jiangxiong, YU Qijun

  Journal of Functional Materials. 2021, 52(7): 7006-7011. https://doi.org/10.3969/j.issn.1001-9731.2021.07.002

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  Single-shell structure hollow silica nanospheres (HSN) are prepared using Stöber method by hydrolyzation-polycondensation of TEOS. Double-ring structure HSN are successfully prepared with single-shell structure HSN as core matrix and adding proper crosslinking agent by stepwise wrapping synthesis method. The microstructure and properties of the as-synthesized products are characterized by XRD spectroscopy, scanning electron microscopy, transmission electron microscopy, nitrogen adsorption-desorption isotherm and thermal conductivity analysis. When the DVB content is 0.2 mL, the shell of the hollow spheres is loose, the layer spacing and specific surface area are 18 nm and 59.81 m²/g, respectively. When the DVB content is 0.3 mL, the hollow spheres have rough morphology and dense shell, the layer spacing and specific surface area are 35 nm and 61.63 m²/g, respectively. With the increase of layer spacing, the thermal conductivity of double-ring structure HSN decreases and could be as low as 0.0252 W/(m·K). Double-ring structure HSN can effectively reduce the thermal conductivity of the coating. The thermal conductivity could be reduced by 85% as the dosage is 8%. The double-ring structure HSN has great application potential in the field of thermal insulation.
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  Preparation of largescale smooth TiN thin film electrode with ultra low resistivity by magnetron sputtering

  TIAN Zhongjie, SHI Shuyan, CHEN Qilei, RUI Xiangxin, HUANG Xinyu, SUN Nana, ZHOU Dayu

  Journal of Functional Materials. 2021, 52(7): 7012-7017. https://doi.org/10.3969/j.issn.1001-9731.2021.07.003

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  In this work, large scale smooth TiN thin film electrode is prepared by RF reactive magnetron sputtering. The effect of substrate bias on the performance and structure of TiN electrode is investigated systematically. The resistivity, composition, preferred orientation, surface morphology and film uniformity of TiN electrodes are characterized by four-point-probe, XPS, GIXRD and AFM. The results show that TiN thin films with ultra-low resistivity can be obtained when a substrate bias of -200 V is applied. At the optimized substrate bias, the TiN electrode deposited on a 4-inch monocrystalline silicon substrate has a good uniformity and consistency. Finally, a HfO₂ MIM capacitor using TiN electrodes is fabricated and tested to shows an excellent paraelectric performance and a low leakage current density.
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  Research on the preparation of NiS₂@MoS₂/CC nanocomposites and electrocatalytic property for hydrogen evolution reaction

  REN Yuxi, CHANG Chuntao, ZHU Shengli, CUI Zhenduo

  Journal of Functional Materials. 2021, 52(7): 7018-7023. https://doi.org/10.3969/j.issn.1001-9731.2021.07.004

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  Hydrogen production by electrolysis is a hot topic in recent years. The electrode catalytic materials are an important factor which would affect the hydrogen evolution reaction. In this paper, three-dimensional NiS₂@MoS₂ composite (NiS₂@MoS₂/CC) is successfully synthesized on carbon cloth via two-step hydrothermal method. The NiS₂ nanosheets vertically arrange on the carbon cloth to support MoS₂ nanoflowers, which is favor in the explosion of the active sites on the edge of MoS₂ and provides a fast material transport channel for hydrogen evolution reaction. The synergistic effect owing to the reasonable interface design improves the surface electron state, further resulting in the improved catalytic activity of the NiS₂@MoS₂/CC composites. The NiS₂@MoS₂/CC has a large electrochemical active area. In 1 M KOH, the composite exhibits relative low hydrogen evolution overpotential of 106 mV at the current density of 10 mA/cm2 and the small Tafel slope of 61.1 mV/dec, which are far better than those of MoS₂/CC and NiS₂/CC.
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  Preparation and biocompatibility of hierarchical porous strucrture on Ti alloys surface via integrated processes

  WU Lihuang, JIN Mingjiang, LIU Jiannan, HAN Jing, JIN Xuejun

  Journal of Functional Materials. 2021, 52(7): 7024-7031. https://doi.org/10.3969/j.issn.1001-9731.2021.07.005

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  The introduction of micro/nano hierarchical porous structure will bring greater specific surface area for the implant surface, increase the thickness of the rough layer, improve the surface wettability, and finally achieve stable and rapid osseointegration. In order to improve the biocompatibility of the titanium alloy implant and improve the success rate of the clinical implant surgery, four kinds of β-type titanium alloys with very low elastic modulus are prepared by alloying in this paper. Super hydrophilic micro/nano hierarchical porous structure is prepared on the surface of titanium alloy by sand blasting, dual-acid etching, and alkali heat treatment. It is confirmed that this structure is beneficial to the deposition of hydroxyapatite. The surface of titanium alloys shows super hydrophilicity (contact angle < 5°). Furthermore, SLA+AT Ti38Nb and SLA+AT Ti2448 samples exhibit the thickest rough layer (3.30 μm), and shows the best biocompatibility. In this study, it is confirmed that the composite process can produce a stable micro-nano hierarchical porous structure on the surface of titanium alloy and this structure is beneficial to improve the biocompatibility of the surface of titanium alloy implant.
Review & Advance
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  Research progress of cathode materials in solid oxide fuel cells

  SHANG Fengjie, LI Qinlan, SHI Yongjing, LIU Haiding, SONG Shigeng

  Journal of Functional Materials. 2021, 52(7): 7032-7040. https://doi.org/10.3969/j.issn.1001-9731.2021.07.006

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  Cathode material is an important component of solid oxide fuel cell. Improving the electron/ion conductivity of cathode materials and reducing the polarization resistance are important methods to make SOFC operate at low temperature and increase the service life of battery. The high electronic conductivity of cathode materials makes perovskite oxides occupy a dominant position in the research field of cathode materials. In this paper, the research progress of perovskite structure cathode, spinel structure cathode and Ruddlesden-popper structure cathode materials is reviewed, and the development direction of cathode materials in the future is prospected.
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  Study on nano rare earth modified high conductivity and heat resistant aluminum alloy conductor material

  LI Hailong, MOU Zhongwu, DING Yi, ZHU Zhixiang, PANG Zhen, LANG Dazhi, LI Luyang, ZHANG Qiang, CHEN Baoan, YANG Changlong

  Journal of Functional Materials. 2021, 52(7): 7041-7045. https://doi.org/10.3969/j.issn.1001-9731.2021.07.007

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  This paper introduces the characteristics of heat-resistant aluminum alloy conductor for transmission line, the advantages and disadvantages of different preparation technologies and the situation of relevant technical standards at home and abroad. The preparation technology of nano rare earth modified high conductivity heat-resistant aluminum alloy conductor material and the current carrying characteristics of the conductor and its application in overhead transmission line engineering are studied. The prospect of large-scale application of nano rare earth modified heat-resistant aluminum alloy with high conductivity in power grid is prospected.
Research & Development
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  First principles study of LiCoO₂ cathode material for lithium ion batteries at different temperatures

  CHEN Zhiqiang, CUI Lei, YANG Lijuan

  Journal of Functional Materials. 2021, 52(7): 7046-7051. https://doi.org/10.3969/j.issn.1001-9731.2021.07.008

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  The evaluation of the thermodynamic properties of electrode materials at a fixed temperature is helpful to accurately describe the performance of lithium ion batteries (LIBS).In order to fully understand the characteristics of layered lithium LiMO₂(M=Co, Ni, Mn), a large number of theoretical calculations has been used to predict the physical and chemical properties of these materials, such as insertion voltage, Li vacancy ordering, Li diffusion, complex transition metal ordering and electron migration path. However, at high power, the battery generates more heat due to high-speed operation, which leads to a series of thermodynamic problems. At present, most studies based on density functional theory (DFT) only consider the thermodynamic properties at 0 K, but ignore the effect of lattice vibration on the properties at high temperature. On the basis of DFT, the relationship between the temperature and the Helmholtz free energy of Li, LiCoO₂ and Li_□CoO₂ is calculated and plotted by accurately simulating the phonon spectrum and lattice vibration of Li,LiCoO₂ and Li_□CoO₂. Accorded to the influence of different temperature, the delithiation potential is modified. It is found that with the increase of temperature, lattice vibration would further cause the decrease of the delithiation potential, which leads to the decrease of the capacity of the cathode material.
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  Study on the photocatalytic performance of high titanium slag-based slag wool on formaldehyde

  LIU Rong, SHEN Xinyu, YANG Xihong, XU Yueqing, HAN Yan, GAO Peng, YAN Xiaoya

  Journal of Functional Materials. 2021, 52(7): 7052-7059. https://doi.org/10.3969/j.issn.1001-9731.2021.07.009

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  In this paper, the high-titanium slag-based slag wool blown from titanium-containing blast furnace slag is selected and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray fluorescence spectroscopy (XRF), fluorescence analysis and Raman spectroscopy. In addition, formaldehyde solution is used as reactant for photocatalytic degradation experiments to explore the photocatalytic degradation ability of high titanium slag based slag cotton to formaldehyde. The results show that the phase of high titanium slag cotton fiber contains perovskite. The average fiber diameter is 0.93 μm. The main oxide composition of high titanium slag based cotton fiber is basic metal oxide, in which the percentage of TiO₂ is 32.99%. Under the irradiation of 254 nm ultraviolet light, the electron-hole pair can be generated, which indicates that the fiber has photocatalytic performance. Perovskite plays a catalytic role in high titanium slag based slag cotton. Under the conditions of room temperature, 1.0 g dosage, 10 min reaction time and 2.5 mW/cm² UV light intensity, the best photocatalytic degradation ability of 400 mL formaldehyde solution with a concentration of 8.0 μg/L is obtained. The total removal rate of formaldehyde is 23.61%, and the photocatalytic degradation rate is 8.96%, accounting for 37.84% of the total removal rate.
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  Controlling the wettability of Pd coating solution and its effect on the uniformity of coating layer

  SONG Kexing, DING Yutian, WU Baoan, HU Yong, CHEN Dingbiao, LU Weiwei, HU Hao, ZHOU Yanjun

  Journal of Functional Materials. 2021, 52(7): 7060-7063. https://doi.org/10.3969/j.issn.1001-9731.2021.07.010

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  The wettability of the coating solution plays an important role in the uniformity of the coating metal nanoparticles on the substrate. Based on the preparation of coating solution contained Pd nanoparticles, the effects of six surfactants, namely, polyvinylpyrrolidone, oleylamine, oleic acid, 1-dodecanethiol, cetyltrimethylammonium bromide, and sodium dodecyl benzene sulfonate, on the surface tension of the coating solution and the contact angle on Cu substrate were investigated. At last, the distribution of Pd nanoparticles of the coating layer was characterized by SEM. The experimental results show that among the six additives, the addition of SDBS can significantly reduce the surface tension and contact angle of the coating solution on Cu substrate, and the uniform Pd coating can be formed on the surface of the substrate when the concentration of the added sodium dodecyl benzene sulfonate is 560 mg/L and the content of Pd nanoparticles in the coating solution is 60 mg/L.
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  Performance of Cu/Mn/La/ MCM-41 zeolite in degrading dye wastewater

  TU Shenghui, XIONG Chaohua, LIN Li, SUN Yinghao, CHEN Jianxin

  Journal of Functional Materials. 2021, 52(7): 7064-7071. https://doi.org/10.3969/j.issn.1001-9731.2021.07.011

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  The three metal composite catalyst Cu/Mn/La/ MCM-41 molecular sieve is synthesized by hydrothermal synthesis method and impregnation method. The morphology and structure of Cu/Mn/La/ MCM-41 molecular sieve samples are studied by means of XRD, SEM, BET and FT-IR. Cu/Mn/La/ MCM-41 molecular sieve is used as catalyst to degrade the reactive black 5 dye wastewater. The catalytic performance of the catalytic degradation of the reactive black 5 dye wastewater is studied and its apparent kinetic equation is obtained. Results show that compared with the material containing a single metal, Cu, Mn, La load can improve the activity of the catalyst. When the crystallization temperature is 120 ℃, Cu load is 20%, the molar ratio of Cu/Mn/La is 15∶5∶2, the surface area and morphology are larger and more regular. Decolorization rate of reactive black 5 after 120 min can reach 95.6%. Cu/Mn/La/MCM-41 molecular sieve catalytic degradation of reactive black 5 dye waste water dynamics is in line with the pseudo first-order kinetics curves.
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  Effect of Mn on the microstructure, texture and magnetic properties of high grade non-oriented silicon steel

  YU Chunlei, LIU Jing, FU Bing, CHENG Zhaoyang

  Journal of Functional Materials. 2021, 52(7): 7072-7078. https://doi.org/10.3969/j.issn.1001-9731.2021.07.012

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  The effect of Mn on the microstructure, texture and magnetic properties of high grade non-oriented silicon steel is investigated in this study by using OM, EBSD and magnetic property measuring instrument. The results show that compared with 0.2Mn, the recrystallization process of the 1.6Mn hot-rolled sheet is largely suppressed, which leads to a significant increase in the strength of the rotating cube texture. After being normalized at 920 °C, the microstructure of normalized plate is significantly recovered compared with hot-rolled plate, and the texture type of hot-rolled plate is basically retained, but the addition of 1.6% Mn has a limited effect on the texture of normalized plate. After annealing at 930 °C, the grain size of 1.6Mn annealed plate is slightly larger than 0.2Mn. At the same time, the unfavorable {111} texture content is almost unchanged and the favorable {100} texture content decreases, which results in a decrease of texture factor, so the magnetic induction B₅₀₀₀ is reduced to 1.644 T from 1.683 T. In the case of the iron loss, P_1.5/50 is reduced to 2.35 W/kg to 2.45 W/kg, while the high frequency iron loss P_1.0/400 is significantly reduced to 17.36 W/kg from 19.29 W/kg after adding 1.6%Mn.
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  Study on preparation and properties of ordinary portland sulphoaluminate cement composite gel system

  WANG Bo, YAN Tiecheng

  Journal of Functional Materials. 2021, 52(7): 7079-7084. https://doi.org/10.3969/j.issn.1001-9731.2021.07.013

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  According to the design proportioning, a ordinary portland sulphoaluminate cement composite gel system was prepared. The factors affecting the properties of common silicate sulphoaluminate cement composite gel system were investigated by the tests of cement paste fluidity, gelation time, stone rate, compressive strength and vertical expansion rate, with changing the mass ratio of ordinary portland cement and sulphoaluminate cement and the water cement ratio and the water reducer dosage .The results show that the fluidity of composite cementitious system is even up to 320 mm when the content of sulphoaluminate cement is 70% (mass fraction), the water binder ratio is 0.5 and the dosage of water reducer is 0.5‰. Its injectability is good. The initial setting time and final setting time are 6min and 14min respectively. The gelation time becomes short. The stone rate is 100% and the vertical expansion rate is about 0.14%. No secondary grouting is needed. The 28 d compressive strength reaches to 43 MPa. The compressive strength, flexural strength and fluidity of the composite cementitious system can be improved by adding appropriate amount of silica fume and silica slag. When the content of silica fume is 10% (mass fraction), the compressive strength and flexural strength of the composite cementitious system reach the peak value at 3 and 28 days. When the content of silicon slag is 15% (mass fraction), the compressive strength and flexural strength of composite cementitious system is up to the maximum at 28 days. When the content of silicon slag is 10% (mass fraction), the fluidity of composite cementitious system reaches 334 mm.
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  Synthesis and excellent sodium storage performance of Ni-Sn alloy quantum dots embedded in porous carbon nanosheets composites

  LI Zhihui, XU Changhong, LIU Peng, GE Yilin, WU Xibing, WANG Feng, YAO Qingrong, Deng Jianqiu

  Journal of Functional Materials. 2021, 52(7): 7090-7095. https://doi.org/10.3969/j.issn.1001-9731.2021.07.015

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  The Sn-based alloy anode materials have attracted wide interest due to their excellent capacity and lower voltage platform during the sodium storage process. Unfortunately, a huge volume change causes the Sn-based anode materials to be easily broken during the charging/discharging processes, resulting in capacity degradation. Herein, the composites composed of Ni-Sn alloy quantum dots embedded in porous carbon nanosheets (Ni-Sn@ PNC) have been synthesized by a simple template method. And the morphological structure and electrochemical performance of the composites Ni₃Sn₄@PNC, Ni₃Sn₂@PNC and PNC have been investigated using structural characterization techniques and electrochemical measurements. The results show that the Ni₃Sn₄@PNC exhibits the best performance among the samples as anodes for sodium-ion batteries. The Ni₃Sn₄@PNC anode delivers a high capacity of 232.7 mAh/g after 100 cycles at 100 mA/g, and the outstanding cycle stability with a capacity retention rate of 81.6% over 1000 cycles at 400 mA/g. The superior electrochemical performance of Ni-Sn alloy anode materials is attributed to the synergistic effect of Ni₃Sn₄ quantum dot and porous carbon nanoplates, shortening the transport distance of charged species, providing high contact area of the electrolyte and active materials, and increasing the reaction active sites. This work provides a feasible strategy for the exploration of new alloy anodes for sodium-ion batteries.
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  Fabrication of TiO₂-NTAs /ZnO heterojunction and its ultraviolet detection performance

  SHANG Shiguang, WANG Rui, LIUYouyao, ZHANG Wenqian, GAO Lang

  Journal of Functional Materials. 2021, 52(7): 7096-7099. https://doi.org/10.3969/j.issn.1001-9731.2021.07.016

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  In this paper, titanium dioxide nanotube arrays/zinc oxide (TiO₂-NTAs/ZnO) heterojunction are prepared on the ITO glass substrate by electron-beam evaporation technology, anodization method and magnetron sputtering technology. The microscopic morphology, element composition, crystal structure, transmittance and UV detection performance of the sample are characterized by SEM, EDS mapping, XRD, Raman, ultraviolet-visible spectrophotometer and electrochemical workstation. The results show that the TiO₂ nanotube arrays with clear surface structure, orderly arrangement, and the uniform pore diameter are anatase structure and grown preferentially along (101). The ZnO film composited of nanoparticles is wurtzite structure and attached to the surface of TiO₂-NTAs. The elements of titanium, oxygen, and zinc are uniformly distributed in the TiO₂-NTAs/ZnO heterojunction. Compared with TiO₂-NTAs, the TiO₂-NTAs/ZnO heterojunction has higher absorptive capacity in the UV-Visible region and can effectively increase the photo-to-dark current ratio and decrease response/recovery time, which is conducive to the practical application of ultraviolet detectors.
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  Preparation and mechanical properties of Ti-Al-Sn-Zr-Mo-Si high temperature titanium alloy

  LIN Zongde, LI Shengwei

  Journal of Functional Materials. 2021, 52(7): 7100-7104. https://doi.org/10.3969/j.issn.1001-9731.2021.07.017

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  Four kinds of Ti-6Al-xSn-4Zr-1Mo-0.8Si-0.5B high temperature titanium alloys (x=2,4,6,8) with different Sn contents are prepared on the basis of based on the approximate α- alloy of Ti-Al-Sn-Zr-Mo-Si system. The structure and composition of the samples are characterized by XRD, SEM and TEM, and the mechanical properties of the samples are tested by electronic universal material testing machine. XRD analysis shows that four kinds of high temperature titanium alloys with different Sn content are composed of single α phase. SEM and TEM analysis show that the four high temperature titanium alloys are composed of lath α phase, and with the increase of Sn content, the width of α lath increases from 0.3 to 0.6 μm. The mechanical properties analysis shows that with the increase of Sn content, the yield strength of high temperature titanium alloy increases gradually, the tensile strength increases first and then decreases, and the elongation decreases gradually. When the Sn content is 8 wt%, the yield strength, tensile strength and elongation of the alloy are 1 466.74, 1 560.38 MPa and 0.68%, respectively.
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  Preparation and photoelectric properties of CH₃NH₃PbI₃ solar cells

  WANG Jin, XIANG Chengmi, ZHANG Yuanyuan

  Journal of Functional Materials. 2021, 52(7): 7105-7109. https://doi.org/10.3969/j.issn.1001-9731.2021.07.018

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  CH₃NH₃PbI₃ perovskite thin films doped with dimethylformamide (DMF) in different proportions are prepared by one-step spin coating method using ether as anti solvent. The crystal structure, morphology, grain size and light absorption performance of CH₃NH₃PbI₃ thin films doped with 0 (pure DMSO), 10%, 30%, 50%, 70% and 100 wt% DMF are studied by X-ray diffraction (XRD), scanning electron microscopy(SEM), element analyzer and UV-Vis spectrophotometer. The results show that the main phase structure of CH₃NH₃PbI₃ thin films prepared by DMF with different ratios is perovskite. With the increased of DMF content, the main peak strength of perovskite first increases and then decreases, and reaches the maximum when DMF content is 70 wt%. When the content of DMF is 50wt%, and when m (DMF): m (DMSO) is 1∶1, the surface of the film is compact and the film coverage is high. The surface of the film is fine equiaxed crystal, and the grain size is between 100 and 200 nm. The absorption edge of all samples is about 780 nm. With the increased of DMF content, the light absorption performance of the films first increases and then decreases. When the content of DMF is 50 wt%, and when m (DMF): m (DMSO) is 1∶1, the film has the best light absorption performance.
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  Preparation and photocatalytic properties of g-C₃N₄ doped Mn Zn ferrite composites

  ZHANG Xiao, WANG Liming, XU Lihui, SHEN Yong, XIE Mingrui

  Journal of Functional Materials. 2021, 52(7): 7110-7118. https://doi.org/10.3969/j.issn.1001-9731.2021.07.019

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  A novel g-C₃N₄ doped Mn-Zn ferrite composite is prepared by self-assembly method, and characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The photocatalytic performance of g-C₃N₄ doped Mn Zn ferrite composite photocatalyst is studied by the degradation effect of Rhodamine B under visible light. The results show that the photocatalytic activity of g-C₃N₄ doped Mn-Zn ferrite (2:3) is higher than that of Mn-Zn ferrite and g-C₃N₄ single components. 0.5g/L sample degrades 96.0% rhodamine B in the solution after 210 minutes of photoreaction. The g-C₃N₄ doped Mn-Zn ferrite photocatalyst possesses characteristics of strong magnetic property and recyclability. After five times of photocatalytic experiments, the degradation rate of g-C₃N₄ doped Mn-Zn ferrite photocatalyst is still more than 90%, Thus it is provided with good application prospect in the degradation of environmental pollutants.
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  Hollow cubic Cu₂S combined with ether electrolyte to improve lithium storage performance

  ZHANG Fa, REN Jing, ZHENG Jianyong, REN Ruipeng, LYU Yongkang

  Journal of Functional Materials. 2021, 52(7): 7119-7123. https://doi.org/10.3969/j.issn.1001-9731.2021.07.020

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  The hollow cubic Cu₂S lithium ion battery anode material is prepared by the sacrificial template method, and the samples are characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), transmission electron microscope (TEM) and physical adsorption instrument. Electrochemical performance are tested by cyclic voltammetry (CV), electrochemical impedance(EIS) and constant current charge-discharge curves. The research results show that the electrode material exhibits excellent electrochemical performance. At a current density of 0.5 A/g, after 350 cycles, it shows a reversible specific capacity of 448 mAh/g. The hollow nanostructure can not only provide a buffer space for volume expansion, but also facilitate the infiltration of the electrolyte and shorten the ion diffusion path. At the same time, the use of ether electrolyte has better compatibility with the material and shows higher electrochemical reversibility.
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  Study on electronic structure and mechanical properties of Cr and La Co-doped SnO₂ by first principles

  XU Jingting, WANG Jingqin, ZHANG Guangzhi, HU Delin, HUANG Guanglin

  Journal of Functional Materials. 2021, 52(7): 7124-7131. https://doi.org/10.3969/j.issn.1001-9731.2021.07.021

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  The SnO₂, the second phase of electrical contact material AgSnO₂, is a wide band-gap semiconductor material. It is difficult to process because of the brittleness and high hardness. In this paper, in order to improve the processability and electrical properties of SnO₂, based on the first principles of density functional theory and the ultrasoft pseudopotential method, the supercell models of SnO₂ single doped and co-doped with Cr and La are established by CASTEP module in Materials Studio. The doping ratio is 16.67%. After geometry optimization, the enthalpy change, charge population, band structure, density of states and elastic modulus of various SnO₂ systems are calculated respectively. And through the simulation results, the changes of electrical and mechanical properties of SnO₂ after doping are analyzed. The result show that all the SnO₂ systems are stable in thermodynamics and kinetics. After doping, the bond population of Sn-O is decreased, and the charge overlap between Sn and O is weakened. The atom O moves to the impurity atom Cr, the bonding ability of Cr-O is stronger, the covalency is high, and the electron transfer is violent. Doping is beneficial to reduce the band gap and improve the conductivity. In all band structrues, due to the hybridization of Cr 3d and La 5d orbitals, the impurity level is formed at Fermi level in Cr-La co-doped SnO₂ system, the energy required for electron transition is greatly reduced, so that the conductivity of Cr-La co-doped SnO₂ system is the best. In terms of mechanical properties, the change trend of shear modulus and elastic modulus of all SnO₂ systems is similar. In Cr-doped SnO₂ system, the ability to resist shear deformation and elastic deformation is improved, the hardness and rigidity are increased, while the toughness and ductility are poorer. In La-doped and co-doped SnO₂ systems, the toughness is improved and the hardness is reduced, and then the processability is improved.
Process & Technology
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  Self-sacrificial template synthesis of Na(La_0.97Yb_0.02Tm_0.01)(WO₄)₂ phosphor and highly pure near-infrared emission

  SUN Meng, HU Zhipeng, ZHANG Lan, ZHANG Fan, WANG Xuejiao

  Journal of Functional Materials. 2021, 52(7): 7132-7136. https://doi.org/10.3969/j.issn.1001-9731.2021.07.022

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  In this work, Na(La_0.97Yb_0.02Tm_0.01)(WO₄)₂ up-conversion phosphor is successfully prepared by self-sacrificing template reaction with a rare earth layered compound (La_0.97Yb_0.02Tm_0.01)₂(OH)₄SO₄·2H₂O as novel template. The developed process allows the direct preparation of the Na(La_0.97Yb_0.02Tm_0.01)(WO₄)₂ via the self-sacrificial reaction without subsequent calcination. The synthesized materials are characterized by powder X-ray diffraction, field emission scanning electron microscopy (FE-SEM) and fluorescence spectroscopy. The results show that the pure phase phosphor can be directly produced by reaction at 200 ℃ for 24 h under WO^2-₄/RE³⁺ molar ratio of 10. FE-SEM analysis shows that using (La_0.97Yb_0.02Tm_0.01)₂(OH)₄SO₄·2H₂O as template, phase-pure double tungstates, whose particles are about 4.6 μm sized micro-disks of favorable dispersion and size uniformity can be obtained without adding any organic reagents. Under the excitation of 978 nm laser, Na(La_0.97Yb_0.02Tm_0.01)(WO₄)₂ phosphor can emit highly pure near-infrared emission at about 796 nm, which is attributed to the ³H₄→³H₆ transition of Tm³⁺ ions. The emission peak at the blue light is almost completely quenched, and the intensity of the near-infrared emission peak is approximately 260 times that of the blue emission peak. Analysis of the UC intensity against excitation power reveals a two-photon mechanism for the phosphor.
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  Synthesis and electrochemical performance of Fe-MOF derived Fe₂O₃@C as anode for lithium ion batteries

  HU Xianwei, TIAN Yifan, WEN Jia

  Journal of Functional Materials. 2021, 52(7): 7137-7142. https://doi.org/10.3969/j.issn.1001-9731.2021.07.023

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  Carbon-coated Fe₂O₃ (Fe₂O₃@C) nanospindles are synthesized by the pyrolysis of MIL-88 precursor. When used as the anode for lithium-ion batteries, this kind of Fe₂O₃@C nanospindles materials can not only promote the contact between the anode and electrolyte, and accommodate the volume change during the cycling, but also improve the conductivity of the based materials. Benefiting from the unique carbon-coated framework structure, the Fe₂O₃@C nanospindles materials present a high initial discharge specific capacity of 1 350 mAh/g, and exhibit an excellent cycling performance (the reversible specific capacity of 800 mAh/g after 100 cycles) and an outstanding rate stability.
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  Preparation and photocatalytic properties of Cu₂O skeleton crystals

  XU Xin, QIU Zhihui, ZHANG Qi, XU Jinyan

  Journal of Functional Materials. 2021, 52(7): 7143-7148. https://doi.org/10.3969/j.issn.1001-9731.2021.07.024

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  With copper acetate as raw material, NaOH as additive, and glutamic acid and sorbitol 1∶1 as reducing agent, Cu₂O skeleton crystal with empty crystal surface is obtained under hydrothermal conditions. XRD, SEM and UV-VIS are used to characterize the crystal structure of Cu₂O and its effect on photocatalysis is researched. According to the analysis, the mixture of glutamic acid and sorbitol results in the reduction of a large amount of Cu²⁺ in the solution to Cu⁺. The solution is extremely saturated, and the crystal edge grows rapidly while the crystal surface does not develop, thus forming the skeleton crystal morphology of Cu₂O. The photocatalytic performance of the skeleton crystal of Cu₂O is better than that of smooth octahedral crystal.
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  G-C₃N₄/Si composites prepared by different precursors for lithium-ion batteries

  TAO Junyan, LIU Huitian, WANG Xiaoyi, LIU Xu, LIU Yuansheng, DAI Xiaoqian, SHAN Zhongqiang

  Journal of Functional Materials. 2021, 52(7): 7149-7157. https://doi.org/10.3969/j.issn.1001-9731.2021.07.025

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  The graphitic carbon nitride materials are prepared via direct polymerization of urea, thiourea, melamine, respectively, then Si@C₃N₄-u, Si@C₃N₄-t, Si@C₃N₄-m are synthesized by compounding with silicon powder. The morphology and crystal structure of the three raw materials and composite materials are characterized by using SEM, TEM, XRD, XPS, FT-IR and BET, and the electrochemical properties are tested by galvanostatic charge-discharge measurements, cyclic voltammetry, and electrochemical impedance spectroscopy. The results indicate that the electrochemical performance of Si@C₃N₄-t is better than Si@C₃N₄-u and Si@C₃N₄-m. C₃N₄-t has a more suitable lamellar and porous structure, and the residual groups on C₃N₄-t can form hydrogen bonds with silicon particles. Some silicon powder can enter the large pores and the gap between the layers, so the volume effect of silicon can be alleviated and the electrochemical stability of the electrode can be improved. The Si@C₃N₄-t electrode delivers a capacity of 971.7 mAh/g at a current density of 500 mA/g after 200 cycles.
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  Study on the SiC growth from Si and Si-Fe alloy

  LI Yaqiong, ZHANG Yanhui, ZHANG Lifeng

  Journal of Functional Materials. 2021, 52(7): 7158-7161. https://doi.org/10.3969/j.issn.1001-9731.2021.07.026

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  The characteristics of SiC crystal growth from Si and Si-Fe alloy melts are investigated with the help of optical microscope and electron probe micro-analysis. It is found that the SiC crystals growth from Si and Si-Fe alloy melts follows the SLS mechanism. Influenced by the solubility of C in the two Si-based melts, the size of SiC crystals in Si melts is small, ranging from 10 μm to 50 μm, which precipitates in a line in the outer region of the sample. The size of SiC crystals in Si-Fe is large, ranging from 50 μm to 200 μm, which disperses in the whole sample.
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  Preparation and performance study of CB/PVDF dry flexible bioelectric potential electrode

  ZHANG Shuaidi, HOU Chengyi, LI Yaogang, ZHANG Qinghong, WANG Hongzhi

  Journal of Functional Materials. 2021, 52(7): 7162-7166. https://doi.org/10.3969/j.issn.1001-9731.2021.07.027

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  The dry flexible bioelectric potential electrode can be directly fitted to the skin surface without conducting medium for bioelectric detection and avoid signal quality degradation caused by water loss of gel electrode, so it can perfectly replace the traditional wet electrode for human health monitoring. In this research, CB/PVDF flexible electrode is prepared with carbon black (CB) and poly (vinylidene fluoride) (PVDF) composite, whose resistivity minimum is 0.3 Ω·cm. The influence of CB content on polarization potential is studied, and it is found that the electrode with CB content of 35 wt% has the most stable polarization potential. Collection of bioelectricity to human body shows that the ECG signal is stable and able to clearly distinguish between P wave, QRS complex and T wave characteristics of ECG signals, and the signal quality is better than Ag/AgCl gel electrode after filtration. CB/PVDF dry type flexible biopotential can replace Ag/AgCl gel electrode, and be used the biological electrical signal monitoring for a long time.
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  Effect of protective atmosphere and sample states on preparation and properties of Nd₂Fe₁₄B magnetic powder by hydrothermal method

  WANG Ling, ZHANG Mingang, ZHU Fengshuai, HU Jifan

  Journal of Functional Materials. 2021, 52(7): 7167-7172. https://doi.org/10.3969/j.issn.1001-9731.2021.07.028

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  The Nd-Fe-B precursor was synthesized by hydrothermal method using as raw materials, and then the magnetic powder with a main phase of Nd₂Fe₁₄B was successfully prepared by reduction-diffusion annealing. Phase composition, magnetic and microstructure of the sample were analyzed by XRD, VSM, SEM, TEM and so on. The influence of the different protective atmosphere (N₂, Ar and 5% H₂/Ar) and the sample states (powder sample and pellet sample) in the process of reduction-diffusion annealing on the composition and performance of product were studied. The results show that Nd₂Fe₁₄B phase can not be synthesized under the protection of N₂, and although it can be synthesized in Ar, its magnetic properties are poor due to the presence of soft magnetic phase and non-magnetic phase impurities.The Nd2Fe14B phase also can not be synthesized by the powder sample. Only under the protection of 5% H₂/Ar and through reduction-diffusion annealing of pellet sample, Nd2Fe14B based magnetic powder with less impurity phase, high magnetic properties and particle size of 0.6-2 μm can be successfully synthesized.
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  Preparation of Li₂SnO₃/WO₃ composites for photocatalytic degradation of Rhodamine B

  PI Mingyu, GUO Lijuan, HE Siqi, YANG Jie, CHEN Shijian, ZHANG Dingke

  Journal of Functional Materials. 2021, 52(7): 7173-7178. https://doi.org/10.3969/j.issn.1001-9731.2021.07.029

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  In this work, Li₂SnO₃/WO₃ composite photocatalysts with different mass fractions are prepared by heat treatment. The photocatalysts are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet-visible spectrophotometer. The photocatalytic activity is tested by degradation of Rhodamine B (RhB). Compared with single phase catalyst, Li₂SnO₃/WO₃ heterojunction photocatalyst has higher degradation efficiency because of the excellent band structure matching between Li₂SnO₃ and WO₃ (Type-II), which enhances the efficient separation of photo-generated carriers. The experimental results show that the optimal performance of Li₂SnO₃/WO₃ composite can be obtained when the mass ratio of WO₃ to Li₂SnO₃ is 3%, which photocatalytic activity is 2.5 times and 8.2 times higher than that of pure Li₂SnO₃ and WO₃, respectively.
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  Preparation of low thermal expansion epoxy functionally gradient materials by magnetic field driving

  SUN Jie, CHEN Zhongtao, KANG Ming, ZHAO Xiuli

  Journal of Functional Materials. 2021, 52(7): 7179-7185. https://doi.org/10.3969/j.issn.1001-9731.2021.07.030

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  In order to reduce the thermal expansion coefficient of epoxy resin, in this paper a low thermal expansion LaFe_10.5Co_1.0Si_1.5/epoxy resin composite material is prepared based on the negative thermal expansion filler LaFe_10.5Co_1.0Si_1.5. Then the influence of LaFe_10.5Co_1.0Si_1.5 filler content on the mechanical properties and thermal expansion properties of the materials is studied. And the gradient distribution of filler particles in the resin matrix is induced by the magnetic field driving method to prepare functional materials with gradient thermal expansion. The results show that LaFe_10.5Co_1.0Si_1.5 can effectively reduce the linear expansion coefficient of epoxy resin-based composites between 228-323 K, and the linear expansion coefficient of the composites can be reduced by 58% when adding 70% LaFe_10.5Co_1.0Si_1.5 filler. In addition, the variation regularities of TGA, thermal conductivity, tensile strength and other properties prove that LaFe_10.5Co_1.0Si_1.5 particles show a gradient distribution along the direction of the magnetic field driven by an external magnetic field. Meanwhile, the thermal expansion properties of the composite materials also show a significant gradient change. These prove that the magnetic field driving method is an effective and simple method for preparing low thermal expansion epoxy gradient materials.
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  Preparation and mechanical properties of nano cellulose doped epoxy resin composites

  YAO Yanfang, YAO Yifan, WANG Yun

  Journal of Functional Materials. 2021, 52(7): 7186-7190. https://doi.org/10.3969/j.issn.1001-9731.2021.07.031

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  A series of epoxy resin composites with different CNF contents (0 wt%, 0.3 wt%, 0.6 wt% and 0.9 wt%) are prepared by miscibility method using epoxy resin E51 as matrix material and nano cellulose (CNF) as doping material. The structure, morphology and mechanical properties of the composites are analyzed by FT-IR, SEM and mechanical properties test. The results show that there is no acetone in the epoxy resin composites doped with CNF, and CNF has been successfully incorporated into the epoxy resin composites. With the addition of CNF, the impact strength, tensile strength, modulus of elasticity and elongation of epoxy resin composites increase first and then decrease, and are higher than pure epoxy resin. When the content of CNF is 0.6 wt%, the impact strength, tensile strength, elongation and elastic modulus of the composites reach the maximum, which are 29.5 kJ/m², 87 MPa, 5.8% and 2 846 MPa, respectively. When the content of CNF is too high, the impact strength, tensile strength, elongation and elastic modulus of the composites decrease. The cross section of pure epoxy resin without CNF is smooth and flat, the fracture direction of the cross section is consistent as a whole, and the fracture mode is brittle fracture. When CNF is added, the fracture surfaces of the composites are rough, and the fracture direction becomes uneven and diversified, and the fracture mode is ductile fracture.
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  Synthesis and properties of heat-resistant polyurethane

  ZENG Xiaoyan, WEN Yi, ZHANG Weili, XIANG Hongxia, LI Youbing, YANG Chaolong

  Journal of Functional Materials. 2021, 52(7): 7191-7196. https://doi.org/10.3969/j.issn.1001-9731.2021.07.032

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  Improving the heat resistance of polyurethane is a hot topic in the application of polyurethane. Polyurethane (PU) is prepared by prepolymer method with polyether polyol (PPG), 4,4′-diphenylmethane diisocyanate (MDI) and 3,3-dichloro-4,4-diaminodiphenylmethane (MOCA) as main raw materials. The effect of chain extension coefficient on the properties of PU is discussed. The results show that with the increase of chain extension coefficient, the comprehensive mechanical properties and heat resistance of PU first increase and then decrease. Dynamic mechanical analysis (DMA) shows that the internal friction peak of glass transition temperature (TG) of PU shifted to high temperature with the increase of chain extension coefficient. When the chain extension coefficient is 0.04, the mechanical properties of polyurethane are the best, the tensile strength is 64.16 MPa, the bending strength is 84.69 MPa, the impact toughness is 8.88 kJ/m², the maximum damping factor (Tan δmax) is 1.108, and the initial thermal decomposition temperature reaches 315 ℃.
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  Preparation and photostatted properties of TNS/C composites by biological template method

  ZHANG Ping, ZHANG Bowen, HAN Lijuan, SU Qiong

  Journal of Functional Materials. 2021, 52(7): 7197-7202. https://doi.org/10.3969/j.issn.1001-9731.2021.07.033

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  A series of TiO₂ nanosheets/carbon (TNS/C) composites are prepared in situ by calcination at high temperature. In the method, the biomass corn stalks which are used as template and carbon source are impregnated in tetrabutyl titanate, then the corn stalks including tetrabutyl titanate are calcined. In the calcination process, biomass forms carbon skeleton and supports TiO₂ nanoparticles, resulting in TiO₂ nano-sheets structure and TNS/C heterogeneous junction. The effect of calculation temperature and template amount on the photocatalytic property of TNS/C composites is investigated. The results show that TNS/C composites prepared at calcination temperature of 700 ℃ and the dosage of template of 0.75 g exhibits optimal photocatalytic performance. The excellent photocatalytic performance of TNS/C composites possibly result from the introdution of carbon. A proper amount of carbon in composite are beneficial to improve the electron-hole separation efficiency, bringing about the significantly improvement of the removal efficiency for phenol under the visible light and mineralization ability.
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  Preparation and properties of all inorganic perovskite CsPbX₃ by supersaturation crystallization

  LI Yuechan, ZHU Jie, XIE An

  Journal of Functional Materials. 2021, 52(7): 7203-7209. https://doi.org/10.3969/j.issn.1001-9731.2021.07.034

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  In recent years, all inorganic lead halide perovskite (CsPbX₃) has become one of the most potential optoelectronic materials because of its excellent optical properties and better stability compared with organic-inorganic hybrid perovskite. In this paper, a series of CsPbX₃ all inorganic perovskite materials are prepared by supersaturated crystallization method at room temperature, which is simple and easy to operate. The effects of ligands, purification times, reaction temperature, storage time and other factors on the phase, microstructure and luminescent properties are investigated. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence (PL) are used to characterize the morphology, crystal structure and optical properties of the samples. The results show that pure phase all inorganic CsPbX₃ perovskite with high crystallinity, regular morphology and good luminescent properties can be prepared by this method. Through the reasonable control of preparation conditions, such as ligands, purification times and so on, nano materials with good stability at room temperature and air environment can be obtained. This method provides a feasible way to explore the next generation of low-cost and high-efficiency fluorescent materials for optoelectronic devices in the future.
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  Preparation and mechanical properties of nano clay/epoxy resin composites

  LI Zhiyuan, CHEN Feng

  Journal of Functional Materials. 2021, 52(7): 7210-7214. https://doi.org/10.3969/j.issn.1001-9731.2021.07.035

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  Nano clay/epoxy resin composites with different nano clay contents (0, 1wt%, 3wt%, 5wt% and 7wt%) are prepared by ultrasonic dispersion and curing treatment, and the effect of nano clay content on the properties of the composite is studied. The composites are characterized by X-ray diffraction (XRD), mechanical properties and scanning electron microscopy (SEM). The results show that the nano clay and epoxy resin with different doping proportion are uniformly combined, and the composite with 7wt% nano clay has the highest diffraction peak intensity and the best crystallization performance. With the increased of nano clay content, the tensile modulus, ultimate compressive strength and fracture toughness KIC values of the composite are higher than those of pure epoxy resin, while the failure strain of the composite is lower than that of pure epoxy resin. When the content of nano clay is 1wt%, the ultimate tensile strength of the composite increases slightly, but with the increase of nano clay content, the ultimate tensile strength of the composite decreases gradually. When the content of nano clay is 5wt%, the tensile modulus of the composite reaches 3513 MPa, which is 6.5% higher than that of pure epoxy resin (3300 MPa). When the content of nano clay is 7wt%, the fracture toughness KIC of the composite is 1.97 MPa·m^1/2, which is 23.1% higher than that of pure epoxy resin (1.60 MPa·m^1/2). The fracture surface of pure epoxy resin is smooth and wrinkle free and the crack does not propagate without deviation, while the fracture surface of composite tends to be rough with the increase of nano clay content, and the crack deviates in the process of propagation.
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  Rapid preparation of Na_1+xZr_2-xFe_x(PO₄)₃ ceramic electrolyte by microwave low-temperature sintering

  ZHANG Xue, WANG Junxia, ZHAN Lei, WEI Yufeng, LI Nan, WANG Yan, WANG Jin

  Journal of Functional Materials. 2021, 52(7): 7215-7220. https://doi.org/10.3969/j.issn.1001-9731.2021.07.036

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  According to the crystal structure characteristics and charge compensation mechanism of NZP-type materials, Fe³⁺-modified NZP ceramic solid electrolytes, Na_1+xZr_2-xFe_x(PO₄)₃ (x=0, 0.1, 0.2, 0.3, 0.4), were designed and prepared by microwave sintering process at 950 ℃ for 1.5 h. The influences of Fe³⁺ on the phase composition, microscopic morphology, relative density, and ionic conductivity of the ceramic electrolyte were systematically studied. The results showed that the single-phase and compact Na_1+xZr_2-xFe_x(PO₄)₃ electrolytes were successfully prepared by microwave sintering at 950 ℃ for holding 1.5 h, which greatly reduced the sintering temperature and shorten the preparation period. With the increase of Fe³⁺ doping amount, the relative density of the sample increased, whose maximum is 93.8%. Moreover, the impedance test results revealed that the addition of Fe³⁺ could improve the ion conductivity of the samples. When the Fe³⁺ doping content was 0.3~0.4, the room-temperature ion conductivity reached 6.5×10^-6 S/cm, and the ion conductivity at high temperature (573 K) was up to 1.56×10^-3 S/cm.