Studying the transition from pseudocapacitive to battery-like desalination for ion selectivity (SELECT)

研究从赝电容到类电池海水淡化的离子选择性 (SELECT) 的转变

• 批准号: 506033205
• 负责人: Professor Dr. Volker Presser
• 金额: --
• 依托单位: Leibniz-Institut für Neue Materialien gGmbH (INM)
• 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/506033205?language=en
• 关键词: Studying; transition; pseudocapacitive; battery; like

The energy transition can only succeed through its analog of the water transition: green energy meets blue water. New technologies for energy-efficient water treatment must be developed for a sustainable future. Electrochemical methods such as capacitive deionization (CDI), made possible by ion electrosorption using electrically charged carbon electrodes, are of particular interest. However, due to the concentration-dependent permselectivity, CDI is limited to very low ion concentrations (brackish water) and depends on the specific surface area of the electrode material. It is also possible to desalinate water by loading Faradaic materials, such as those that enable intercalation (Faradaic deionization: FDI). A typical FDI material is metal oxides that are capable of cation intercalation. FDI also works with high salt concentrations (seawater) and, due to the higher charge storage capacity, also enables higher desalination capacities. However, the slower ion diffusion in metal oxides limits the desalination rates of FDI systems. CDI and FDI have in common that the aqueous medium to be desalinated flows past two electrodes.In addition to pseudo-capacitive desalination, the technology of desalination batteries represents one of two FDI mechanisms. In desalination batteries, ions are immobilized at specific intercalation potentials. In the case of pseudocapacitors, incorporating ions is possible continuously at every applied potential. Battery-like processes, which are more subject to diffusion limitations, can potentially allow high selectivity for an ionic species. In contrast, the faster process of pseudocapacity can be less selective. As a function of the crystal structure, the transition between these two processes has not yet been addressed in detail. Neither does how the ion selectivity changes during material aging. Therefore, it is of great interest to know how desalination capacity, rate, energy efficiency, and ion selectivity change. This is because ion-selective and high-performance desalination technologies are of great importance for the recovery of raw materials, the removal of pollutants and the generation of clean water for the drinking water supply, and the production of hydrogen via electrolysis.Our project will specifically apply metal oxides (vanadium oxide and molybdenum oxide) to carbon materials with an outer surface (carbon nano onions and carbon nanotubes). To do this, we use the atomic layer deposition (ALD) method that can be controlled on the nanoscale. In addition to comprehensive material characterization, we will record the electrochemistry in half and full cells and conduct desalination experiments with low and high ion concentrations. The electrode aging, the ion immobilization mechanism, and the resulting performance parameters of desalination and ion selectivity are addressed in detail.

能量转换只有通过类似于水的转换才能成功：绿色能量遇到蓝色的水。为了可持续的未来，必须开发新的节能水处理技术。电化学方法，如电容去离子（CDI），通过使用带电碳电极的离子电吸附成为可能，是特别感兴趣的。然而，由于浓度依赖性选择渗透性，CDI仅限于非常低的离子浓度（微咸水），并取决于电极材料的比表面积。还可以通过加载法拉第材料（例如能够嵌入的那些（法拉第去离子：FDI））来淡化水。典型的FDI材料是能够进行阳离子嵌入的金属氧化物。FDI也适用于高盐浓度（海水），并且由于更高的电荷存储容量，也可以实现更高的脱盐能力。然而，金属氧化物中较慢的离子扩散限制了FDI系统的脱盐速率。CDI和FDI的共同点是要脱盐的水介质流过两个电极。除了伪电容脱盐，脱盐电池技术代表了两种FDI机制之一。在脱盐电池中，离子被固定在特定的嵌入电位下。在赝电容器的情况下，掺入离子是可能的，在每个施加的电位连续。更容易受到扩散限制的电池类工艺可以潜在地允许对离子物质的高选择性。相比之下，伪容量的更快过程可能选择性更小。作为晶体结构的函数，这两个过程之间的过渡尚未详细解决。也不知道在材料老化期间离子选择性如何变化。因此，了解脱盐能力、速率、能量效率和离子选择性如何变化是非常有意义的。这是因为，离子选择性高性能海水淡化技术对于原材料的回收、污染物的去除、饮用水的清洁水的生成、电解制氢等都具有重要意义。本项目将金属氧化物（氧化钒、氧化钼）具体应用于具有外表面的碳材料（纳米碳洋葱、纳米碳管）。为此，我们使用可以在纳米尺度上控制的原子层沉积（ALD）方法。除了全面的材料表征外，我们还将记录半电池和全电池的电化学，并在低和高离子浓度下进行脱盐实验。电极老化，离子固定机制，以及由此产生的性能参数的脱盐和离子选择性的详细解决。