Alkaline water electrolysis with gas-diffusion electrodes

使用气体扩散电极电解碱性水

• 批准号: 450621348
• 负责人: Professor Dr.-Ing. Thomas Turek
• 金额: --
• 依托单位: Institut für Chemische und Elektrochemische Verfahrenstechnik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/450621348?language=en
• 关键词: Alkaline; water; electrolysis; gas; diffusion

In the proposed project, an experimental and theoretical study on the use of gas-diffusion electrodes (GDE) for alkaline water electrolysis in a novel „hybrid“ cell configuration in combination with a classical gas evolving electrode shall be conducted. Main emphasis is placed on the use of the GDE for oxygen evolution, since this configuration was already successfully demonstrated in previous work. Additionally, GDE shall be also employed for hydrogen evolution. First, a series of GDE with nickel and iron as electro-catalysts will be prepared and characterized with physico-chemical methods in order to achieve a broad variation of composition and pore system properties of the GDE. Subsequently, the GDE are tested in a special cell, that allows to determine the overvoltage at the GDE as a function of current density at different process conditions (temperature, electrolyte concentration, differential pressure between electrolyte and gas as well as contact pressure of the separator electrode assembly. In this way, structure-property relationships shall be determined and the most promising electrodes for the following investigations can be selected. On important goal of these further measurements is the determination of the performance limit of the newly developed cell configuration as a function of process conditions and GDE properties. Furthermore, quantitative information on the purity of the evolving oxygen shall gathered in order to test the hypothesis that the gas purity is mainly determined by the permeability of the separator and significantly higher than in the case of mixed electrolyte cycles in a classical cell. Moreover, measurements with a longer duration will deliver information about the crossover of electrolyte and condensate through the GDE as well as about the GDE stability. In an exploratory work package, the GDE will be also used as cathode in order to investigate the differences resulting from the stronger hydrogen gas evolution. Parallel to the experimental work packages, a mathematical modell will be developed with which the interaction between electrochemical reaction and the different transport processe in the GDE can be described and the overvoltage as a function of the process conditions can be calculated. In this way can the main loss mechanisms be clarified and model-based approaches for improved GDE can be developed.

在拟议的项目中，将进行一项实验和理论研究，研究在一种新型的“混合”电池配置中使用气体扩散电极（GDE）与传统的气体释放电极相结合进行碱性水电解。主要的重点放在使用的GDE的析氧，因为这种配置已经成功地证明了在以前的工作。此外，GDE还应用于析氢。首先，将制备一系列具有镍和铁作为电催化剂的GDE，并用物理化学方法表征，以实现GDE的组成和孔系统性质的广泛变化。随后，在特殊电池中测试GDE，其允许确定在不同工艺条件（温度、电解质浓度、电解质和气体之间的压差以及隔膜电极组件的接触压力）下作为电流密度的函数的GDE处的过电压。通过这种方式，可以确定结构-性能关系，并为以下研究选择最有前途的电极。这些进一步测量的一个重要目标是确定新开发的电池配置的性能极限作为工艺条件和GDE性质的函数。此外，应收集关于放出的氧气的纯度的定量信息，以检验气体纯度主要由隔板的渗透性确定并且显著高于在经典电池中的混合电解质循环的情况下的气体纯度的假设。此外，具有较长持续时间的测量将提供关于电解质和冷凝物通过GDE的交叉以及关于GDE稳定性的信息。在探索性工作包中，GDE也将用作阴极，以研究由更强的氢气释放产生的差异。与实验工作包并行，将开发一个数学模型，用它可以描述GDE中电化学反应和不同传输过程之间的相互作用，并可以计算作为过程条件的函数的过电压。通过这种方式，可以澄清主要的损失机制，并可以开发基于模型的方法来改进GDE。