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建立具有外置双饱和甘汞参比电极及双液流电池的实验装置系统.使用该装置可在同一时刻同时测定小型液流单电池充放电时的电池电压、电池正负极电位及正负极开路电位,进而计算充放电过程电池的欧姆内阻降(iR)及其正负极过电位.以石墨毡为电极、Nafion 117作隔膜的全钒液流单电池,在60 mA.cm-2电流密度下,每一充放电循环的平均iR降约占总电压损耗的74%,表明该电池的电压效率受制于电池的欧姆内阻.充放电曲线显示,电池放电终点之所以出现主要是由于电池负极电位在放电末期的快速上升而引起的.本文设计的全钒单电池于60 mA.cm-2下工作时,其电压及能量效率分别达89%和85%,表明该电池结构合理,且石墨毡是钒电池合适的电极材料. 相似文献
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许多现代分析仪器如气相色谱仪等.迫切需要一种操作简单、安全可靠的小型氢气发生器来提供具有一定压力的高纯氢气,以取代繁琐笨重的高压氢气瓶及其净化系统. 一、原理和流程 众所周知,水经电解即可生成氢气和氧气。但如何有效地将它们分离开,并确保氢气具有一定的压力,是制造这种制氢机的技术关键。目前,国内外生产的这类制氢机均采用以下两种方法来解决这一技术问题。一是采用钯—银膜做为电解池的阴极。这 相似文献
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The kinetic characteristics of the concentrated Ⅴ(Ⅳ)/Ⅴ(Ⅴ) couple have been studied at a glassy carbon electrode in sulfuric acid using rotating-disc electrode and cyclic voltammetry. The kinetics of the Ⅴ(Ⅳ)/Ⅴ(Ⅴ) redox couple reaction was found to be electrochemically quasi-reversible with the slower kinetics for the Ⅴ(Ⅴ) reduction than that for the Ⅴ(Ⅳ) oxidation. And, dependence of diffusion coefficients and kinetic parameters of Ⅴ(Ⅳ) species on the Ⅴ(Ⅳ) and H2SO4 concentration was investigated. It is shown that the concentration of active species Ⅴ(Ⅳ) should be over 1 mol·L^-1 for the redox flow battery application. Further, with increasing the Ⅴ(Ⅳ) and H2SO4 concentration, the diffusion coefficients of Ⅴ(Ⅳ) were gradually reduced whereas its kinetics was improved considerably, especially in the case of Ⅴ(Ⅳ) and H2SO4 up to 2 and 4 mol·L^-1. 相似文献
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本文提出一种新颖简易的方法制备PEMFC的亲水型薄层MEA,其阴、阳极催化层Pt担量分别为0. 4和 0. 2mg/cm2.实验发现,在亲水型MEA的表面上,有大量钟乳石状细微颗粒存在,从而使电极催化层的比表面积增大.在小电流密度区( <1A/cm2 ),亲水型MEA的极化性能差于Pt担量为 0. 7mg/cm2的疏水型常规MEA,但在大电流密度区( >2A/cm2 ),则前者的极化性能优化后者;亲水型MEA的最大输出比功率为1. 23W/cm2,高于疏水型电极的 1. 19W/cm2;在大电流密度区,亲水型MEA中的Pt电化学比活性也明显高于疏水型电极. 相似文献
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以金属有机骨架为前驱体的高活性氧还原非贵金属催化剂制备 总被引:1,自引:0,他引:1
The development of a non‐precious metal electrocatalyst (NPME) with a performance superior to commercial Pt/C for the oxygen reduction reaction (ORR) is important for the commercialization of fuel cells. We report the synthesis of a NPME by heat‐treating Co‐based metal organic frameworks (ZIF‐67) with a small average size of 44 nm. The electrocatalyst pyrolyzed at 600 °C showed the best performance and the performance was enhanced when it was supported on BP 2000. The resulting electrocatalyst was composed of 10 nm Co nanoparticles coated by 3–12 layers of N doped graphite layers which as a whole was embedded in a carbon matrix. The ORR performance of the electrocatalyst was tested by rotating disk electrode tests in O2‐saturated 0.1 mol/L KOH under ambient conditions. The electrocatalyst (1.0 mg/cm2) showed an onset potential of 1.017 V (vs. RHE) and a half‐wave potential of 0.857 V (vs. RHE), which showed it was as good as the commer‐cial Pt/C (20μgPt/cm2). Furthermore, the electrocatalyst possessed much better stability and re‐sistance to methanol crossover than Pt/C. 相似文献
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锂离子电池聚阴离子型正极材料 总被引:1,自引:0,他引:1
聚阴离子型正极材料具有高安全性、低成本和环境友好等优点,是最具潜力的车用动力锂离子电池正极材料之一,但是较低的电子电导率和离子电导率以及较差的倍率性能和低温性能限制了这类材料的实际应用。近年来,通过对材料进行表面包覆电子良导体、体相掺杂以及制备纳米尺寸材料等,显著提升了部分聚阴离子型正极材料的电化学性能;同时,还实现了磷酸亚铁锂在车用动力电池中的实际应用。本文论述了近年来聚阴离子型正极材料研究领域中的研究热点及进展,特别是近几年重新成为研究热点的硅酸盐和硫酸盐正极材料,重点讨论了各种聚阴离子型正极材料的晶体结构、合成及改性方法、电化学性质、安全性以及实际应用所面临的技术瓶颈等,最后探讨了提升材料性能的可能途径。 相似文献
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