The formation of periodic layered structure in Ni3Si/Zn diffusion couples with Zn in vapor or liquid state was investigated by SEM-EDS, FESEM and XRD. The results show that the diffusion path in solid-liquid reaction ...The formation of periodic layered structure in Ni3Si/Zn diffusion couples with Zn in vapor or liquid state was investigated by SEM-EDS, FESEM and XRD. The results show that the diffusion path in solid-liquid reaction is Ni3Si/（T＋γ）/γ/…T/γ/Ni4Zn12Si3/γ/…Ni4Zn12Si3/γ/Ni4Zn12Si3/δ…/Ni4Zn12Si3/δ/liquid-Zn, and the diffusion path in solid-vapor reaction is Ni3Si/θ/（T＋γ）/γ/…/T/γ/…T/γ/vapor-Zn. With increasing Zn diffusion flux, the diffusion reaction path moves toward the Zn-rich direction, and the distance from the Ni3Si substrate to the periodic layer pair nearest to the interface decreases. In the initial stage of both reactions,γphase nucleates and grows within T matrix phase at first, and then conjuncts together to form a band to reduce the surface energy. Based on the experimental results and diffusion kinetics analysis, the microstructure differences were compared and the formation mechanism of the periodic layered structure in Ni3Si/Zn system was discussed.展开更多
Flexible aqueous Ni//Zn batteries have attracted much attention as promising candidates for energy storage in the field of flexible electronics.However,the Ni-based cathodes still face the challenges of poor conductiv...Flexible aqueous Ni//Zn batteries have attracted much attention as promising candidates for energy storage in the field of flexible electronics.However,the Ni-based cathodes still face the challenges of poor conductivity,confined charge/mass transfer,and non-flexibility.In this work,we designed a hollow tubular structure consisting of a conductive silver nanowire (Ag NW) wrapped by active Ni Co layered double hydroxide (LDH),for enhancing the electrical conductivity,improving the charge/mass transfer kinetics,and facilitating the ion penetration.By optimizing the contents of Ni,Co and Ag NW,the Ni_(4)Co LDH@Ag_(1.5)NW composite shows a maximum specific capacity of 115.83 m Ah g^(-1)at 0.1 A g^(-1)measured in a two-electrode system.Highlightingly,the flexible aqueous Ni//Zn battery assembled by Ni_(4)Co LDH@Ag_(1.5)NW interwoven with multi-walled carbon nanotube cathode and Zn foil anode realizes a high power density of 160μW cm^(-2)at the energy density of 23.14μWh cm^(-2),which is superior compared with those of oxide/hydroxide based devices and even higher than those of many carbon-based supercapacitors,showing its promising potentials for flexible energy storage applications.展开更多
利用化学共沉淀法制备纳米Mn-Zn铁氧体磁流体,再以一定比例将其掺入水泥浆体制备吸波层,以膨胀珍珠岩作为匹配层,制备双层水泥基吸波材料,研究了不同纳米组分掺入量对该种水泥基材料吸波性能的影响。结果表明:纳米Mn-Zn铁氧体吸波砂浆...利用化学共沉淀法制备纳米Mn-Zn铁氧体磁流体,再以一定比例将其掺入水泥浆体制备吸波层,以膨胀珍珠岩作为匹配层,制备双层水泥基吸波材料,研究了不同纳米组分掺入量对该种水泥基材料吸波性能的影响。结果表明:纳米Mn-Zn铁氧体吸波砂浆在厚度(20+10)mm、掺量7%时,在8~18 GHz频段内反射率都小于-10 d B,最小反射率为18 GHz处的-15.1 d B。展开更多
基金Projects(51271040,51171031)supported by the National Natural Science Foundation of ChinaProject supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘The formation of periodic layered structure in Ni3Si/Zn diffusion couples with Zn in vapor or liquid state was investigated by SEM-EDS, FESEM and XRD. The results show that the diffusion path in solid-liquid reaction is Ni3Si/（T＋γ）/γ/…T/γ/Ni4Zn12Si3/γ/…Ni4Zn12Si3/γ/Ni4Zn12Si3/δ…/Ni4Zn12Si3/δ/liquid-Zn, and the diffusion path in solid-vapor reaction is Ni3Si/θ/（T＋γ）/γ/…/T/γ/…T/γ/vapor-Zn. With increasing Zn diffusion flux, the diffusion reaction path moves toward the Zn-rich direction, and the distance from the Ni3Si substrate to the periodic layer pair nearest to the interface decreases. In the initial stage of both reactions,γphase nucleates and grows within T matrix phase at first, and then conjuncts together to form a band to reduce the surface energy. Based on the experimental results and diffusion kinetics analysis, the microstructure differences were compared and the formation mechanism of the periodic layered structure in Ni3Si/Zn system was discussed.
文摘采用静电纺丝法制备了平均直径分别为180 nm和220 nm的BaTiO3（BTO）和Ni0.4Co0.2Zn0.4Fe2O4（NCZFO）纳米纤维,使用X射线衍射（XRD）、场发射扫描电镜（FESEM）和矢量网络分析仪（VNA）对纤维的物相结构、表面形貌和微波电磁参数进行了表征,并根据传输线理论分析评估了以BTO和NCZFO纳米纤维为吸收剂的硅橡胶基单层和双层结构吸波涂层在2~18 GHz范围内的微波吸收性能。结果显示,由于BTO纳米纤维的介电损耗与NCZFO纳米纤维的磁损耗的有机结合和阻抗匹配特性的改善,以NCZFO纳米纤维/硅橡胶复合体（S1）为匹配层、BTO纳米纤维/硅橡胶复合体（S2）为吸收层的双层吸波涂层比相应单层吸波涂层表现出更为优异的吸收性能。通过调节匹配层与吸收层的厚度,在4.9~18 GHz范围内反射损耗可达–20 d B以下;当吸收层和匹配层的厚度分别为2.3 mm和0.5 mm时,最小反射损耗位于9.5 GHz达–87.8 d B,低于–20 d B的吸收带宽为5 GHz。优化设计的NCZFO/BTO纳米纤维双层吸波涂层有望发展成为一种新型的宽频带强吸收吸波材料。
基金sponsored by the National Natural Science Foundation of China(61804054)the Natural Science Foundation of Shanghai(18ZR1410400)+2 种基金the Shanghai Sailing Program(17YF1403300)the Shanghai Aerospace Science and Technology Innovation Fundation(SISP2018)the Shanghai Aerospace Science and Technology Innovation Fund(SAST2019-067)。
文摘Flexible aqueous Ni//Zn batteries have attracted much attention as promising candidates for energy storage in the field of flexible electronics.However,the Ni-based cathodes still face the challenges of poor conductivity,confined charge/mass transfer,and non-flexibility.In this work,we designed a hollow tubular structure consisting of a conductive silver nanowire (Ag NW) wrapped by active Ni Co layered double hydroxide (LDH),for enhancing the electrical conductivity,improving the charge/mass transfer kinetics,and facilitating the ion penetration.By optimizing the contents of Ni,Co and Ag NW,the Ni_(4)Co LDH@Ag_(1.5)NW composite shows a maximum specific capacity of 115.83 m Ah g^(-1)at 0.1 A g^(-1)measured in a two-electrode system.Highlightingly,the flexible aqueous Ni//Zn battery assembled by Ni_(4)Co LDH@Ag_(1.5)NW interwoven with multi-walled carbon nanotube cathode and Zn foil anode realizes a high power density of 160μW cm^(-2)at the energy density of 23.14μWh cm^(-2),which is superior compared with those of oxide/hydroxide based devices and even higher than those of many carbon-based supercapacitors,showing its promising potentials for flexible energy storage applications.
文摘利用化学共沉淀法制备纳米Mn-Zn铁氧体磁流体,再以一定比例将其掺入水泥浆体制备吸波层,以膨胀珍珠岩作为匹配层,制备双层水泥基吸波材料,研究了不同纳米组分掺入量对该种水泥基材料吸波性能的影响。结果表明:纳米Mn-Zn铁氧体吸波砂浆在厚度(20+10)mm、掺量7%时,在8~18 GHz频段内反射率都小于-10 d B,最小反射率为18 GHz处的-15.1 d B。
