Central subproject: Preparation and characterization of technical silver electrodes

气体扩散电极（GDE）是燃料电池和金属-空气电池等相关电化学过程的关键部件，对能量转换具有重要意义。在拟建的研究单元中，以碱性电解液中银基GDE的氧还原为例进行研究。这些GDE的制备方法必须保证高的电催化活性，低的电子电阻以及高的化学和机械稳定性。GDE孔系统的形态对这些要求起着决定性的作用，因为只有亲疏水性质的适当结合才能使液体电解质、气态氧和电催化剂之间产生密切的接触。到目前为止，对gde的详细描述只是部分可行的。这是由于过程的复杂相互作用，缺乏使用工作gde进行空间分辨的原位和操作观测的方法，以及具有良好物理化学基础的模型的有限可用性造成的。提议的研究单位应结合电极制备，断层扫描，相分布和传输建模，微观电化学以及所有相关尺度上微观和宏观动力学的分析和建模等领域的能力。因此，传递和反应过程的复杂相互作用可以被理解和定量描述。在拟议的中心项目中，电极的制备和表征以及半电池的制造将为所有合作伙伴进行。

Gas-diffusion electrodes (GDE) are key components for several relevant electrochemical processes such as fuel cells and metal-air batteries with fundamental importance for the energy turnaround. In the proposed research unit, the oxygen reduction over silver-based GDE in alkaline electrolyte shall be studied as an example. The preparation methods for these GDE must ensure high electro-catalytic activity, low electronic resistance as well as high chemical and mechanical stability. The morphology of the GDE pore system plays a decisive role for these requirements, since only a proper combination of hydrophilic and hydrophobic properties gives rise to intimate contact between liquid electrolyte, gaseous oxygen and the electro-catalyst. A detailed description of GDEs has been until now only partially possible. This is caused by the complex interplay of processes, missing methods for spatially resolved in situ and in operando observations using working GDEs, and the limited availability of models with sound physico-chemical basis. The proposed research unit shall combine competencies in the fields of electrode preparation, tomography, modeling of phase distribution and transport, micro-electrochemistry as well as analysis and modeling of micro- and macro-kinetics on all relevant scales. Thus, the complex interaction of transport and reaction processes can be understood and quantitatively described. In the proposed central project, the preparation and characterization of electrodes as well as the manufacture of half cells will be conducted for all partners.