低温燃料电池用催化剂载体的研究

对目前普遍使用的碳黑载体,以及碳纳米管、介孔碳和碳气凝胶等新型碳载体作为低温燃料电池催化剂载体进行了评述,并对导电陶瓷作为燃料电池催化剂载体的可行性进行了探讨。最后,本文对低温燃料电池催化剂载体研究进行了展望。     

Highly transparent low resistance ATO/AgNWs/ATO flexible transparent conductive thin films

Indium-free flexible transparent conductive thin films (TCFs) composed of silver nanowire (AgNW) networks and Sb doped SnO₂ (ATO) layers were prepared on polyethylene terephthalate (PET) substrates. The ATO layers were deposited via radio frequency (RF) magnetron sputtering at room temperature. The AgNWs were achieved via a modified polyol reduction method and embedded between the ATO layers. The effects of AgNW networks and ATO layers on electrical and optical properties of the ATO/AgNWs/ATO flexible tri-layer thin films are investigated. The ATO layers can improve the optical transmittance and reduce the resistivity of tri-layers, and the corresponding mechanisms are proposed. Typically, an ATO/AgNWs/ATO flexible tri-layers show a high figure of merit value (30.06 × 10^-3 Ω^-1) with a low sheet resistance of 7.1 Ω/sq. and a high transmittance of 85.7%. Meanwhile, the tri-layers present excellent mechanical flexibility, and the ATO layers acted as the protecting layers improve the adhesive and environmental stability at high temperature and humidity for the ATO/AgNWs/ATO flexible tri-layers. These results indicate that ATO/AgNWs/ATO flexible tri-layer thin films can be useful for the fabrication of wearable electronic devices.     

Application of the cold sintering process to the electrolyte material BaCe0.8Zr0.1Y0.1O3-δ

This paper describes and discusses the application of the original sintering process named cold sintering to the electrolyte material BaCe_0.8Zr_0.1Y_0.1O_3-δ to enhance its densification at a temperature below that needed in a conventional sintering. This new technique enables the acceleration of the densification resulting in a more compacted microstructure with an unexpected high relative density of 83 % at only 180 °C. A subsequent annealing at 1200 °C further enhances the densification which reaches 94 %. The electrochemical performance of CSP sintered ceramics was investigated and optimized by varying different process parameters. The comparison with the conventional sintered material reveals an increase of the total conductivity by mostly increasing the grain boundary one. This result emphasizes the benefits of CSP to not only reduce the sintering temperature but also to enhance the electrochemical properties.     

Product design: Formulation of a screen-printable sintering-type conductive paste

Due to the complexity of the screen-printing operation and the rheological behaviors of the screen-printable paste, such a paste is usually formulated by trial-and-error. In this report, a systematic procedure, based on heuristics and mechanistic models, for the design of a screen-printable paste is developed. The procedure is demonstrated by a case study of the formulation of a conductive paste of copper particles.     

导热绝缘PE-LD/PE-g-MAH/h-BN泡沫塑料的制备及性能研究

采用熔融共混法制备了一系列导热绝缘的低密度聚乙烯/马来酸酐接枝聚乙烯/六方氮化硼(PE-LD/PE-g-MAH/h-BN新型泡沫塑料,研究了相容剂PE-g-MAH的加入、h-BN含量对PE-LD/PE-g-MAH/h-BN泡沫体系导热性能、绝缘性能、力学性能及热稳定性的影响。结果表明,PE-g-MAH有利于增加PE?LD与h?BN的界面黏结,增强泡沫体系拉伸强度和断裂伸长率,显著提高其热导性能;当h-BN含量为30 %时, PE-LD/PE-g-MAH/h-BN泡沫体系的导热率为0.256 W/(m·K),相对于PE-LD/h-BN泡沫体系的0.217 W/(m·K) 和纯PE-LD泡沫体系的0.039 W/(m·K),热导率分别提高1.18和6.57倍,同时保持较好的绝缘性和热稳性。     

聚苯胺微纤维的热稳定性

以对甲苯磺酸(TSA)为掺杂剂合成的平均直径为160 nm纤维形貌聚苯胺(PA n i-TSA)为研究对象,采用SEM、TGA、FT-IR、XRD及XPS等分析手段探讨了热处理温度对其电导率、形貌及结构的影响。结果表明,在空气气氛中,PA n i-TSA微纤维样品的室温电导率在热处理温度低于150℃时具有良好的稳定性;当热处理温度超过150℃后,因掺杂剂TSA从聚苯胺分子链中脱出而导致其电导率逐渐下降;当热处理温度为250℃时,样品的电导率比热处理前下降了9个数量级。随着热处理温度的升高,纤维形貌的PA n i-TSA的平均直径增大,其结晶度也逐渐下降。     

壳核型聚苯胺/钛酸钡复合电流变材料的制备及表征

采用溶液聚合的方法,在经过硅烷偶联剂表面修饰的钛酸钡微粉表面原位聚合聚苯胺,得到聚苯胺/钛酸钡壳核结构(BaTiO3/PAn)的有机-无机复合粒子.借助SEM、XRD、FT-IR、DSC-TG等分析手段研究了复合粒子的形貌、结构及热性能.利用改装后的旋转粘度计分别对钛酸钡和聚苯胺/钛酸钡复合颗粒的电流变性能进行研究.结果表明利用硅烷偶联剂成功地在钛酸钡粒子表面接枝合成聚苯胺,聚苯胺/钛酸钡复合颗粒电流变液的电流变性能明显比纯钛酸钡的电流变性能有所提高.     

铈掺杂双钙钛矿氧化物Gd_2NiMnO_6的电运输性质

采用传统高温固相反应法制备了双钙钛矿氧化物Gd_((2-x))CexNiMnO_6(x=0,0.1,0.2,0.3)多晶样品。通过样品的XRD谱及电阻率随温度的变化数据(ρ-T曲线)研究了样品的结构和电运输性质。结果表明:该组样品均呈现良好的单相性,属于单斜晶系,空间群为P2_1/n;该组样品均属于半导体材料,磁场的存在不利于电传导;随着铈元素的掺杂,导电性越来越好;在所测温度区间内,铈的较高浓度掺杂改变了其导电方式,导电机制由变程跳跃方式转变为热激活方式。     

水性镍系电磁屏蔽涂料导电与屏蔽效能研究

以导电镍粉与丙烯酸乳液为主要原料,制备针对建筑物内墙使用的水性镍系电磁屏蔽涂料,对其导电镍粉和涂层的微观形貌进行表征,并对其导电性和屏蔽效能进行检测。结果表明,导电镍粉由于具有毛刺状突起,因此可以增加涂层的电导率,降低渗滤值;涂层的电磁屏蔽效能取决于涂层的厚度与镍粉含量。     

石墨电极电火花加工非导电陶瓷SiO2实验研究

以导电胶涂层作为辅助电极、石墨作为工具电极,用实验的方法考察了电火花加工非导电陶瓷SiO2的可行性;证明在正极性加工条件下,石墨电极能增强导电膜生成,提高加工稳定性;并给出了脉冲宽度、加工电流等电参数对加工速度、电极损耗及表面质量等工艺指标的影响规律,得出了一些有益的结论.