Periodic Reporting for period 1 - DYONCON (Dynamic Ions under Nano-Confinement for Porous Membranes with Ultrafast Gas Permeation Control)
Reporting period: 2022-07-01 to 2024-12-31
Transport phenomena of molecules and ions inside porous materials are paramount in various fields, ranging from energy storage and transformation to molecular separation. In advanced energy storage devices, like supercapacitors and batteries, ions are confined in small pores. Nanoconfinement effects change the ion properties and enhance the performance, vital for saving resources and energy. So far, the static properties of nanoconfined ions are thoroughly studied but there is little known about the dynamic properties of ions in nanopores, mainly attributed to the lack of suitable experimental model systems.
Here, the dynamic properties of nanoconfined ions will be explored by using well-defined, tunable model systems. This is realized by combining two exclusive material classes: ionic liquids, ILs, which are room-temperature molten salts of organic molecules, and films of metal-organic frameworks, MOFs. MOF films provide the variable, crystalline, scaffold-like container for the ion confinement. An applied electric field will act on the nanoconfined ILs, causing its directed movements. Controlling the dynamic properties of the nanoconfined ions will lead to myriad advances of safety and efficiency concerns, including enhanced charging rates of energy storage devices.
In a new approach, we will also show that nanoconfined ions provide unprecedented functionalities. Based on the functional uniformity of IL@MOF membranes, the nano-level control of the confined ions will be used to regulate macroscopic gas fluxes with ultrafast switching rates.
This project aims to enhance the potentials of electrochemical technologies in energy storage, in sensors and in iontronics. The benefits will not only impact the improvement of speed, quality and control in existing technologies, but it will change the way we look at mobile confined ions and launch us into new methods of using nanomaterials.
Here, the dynamic properties of nanoconfined ions will be explored by using well-defined, tunable model systems. This is realized by combining two exclusive material classes: ionic liquids, ILs, which are room-temperature molten salts of organic molecules, and films of metal-organic frameworks, MOFs. MOF films provide the variable, crystalline, scaffold-like container for the ion confinement. An applied electric field will act on the nanoconfined ILs, causing its directed movements. Controlling the dynamic properties of the nanoconfined ions will lead to myriad advances of safety and efficiency concerns, including enhanced charging rates of energy storage devices.
In a new approach, we will also show that nanoconfined ions provide unprecedented functionalities. Based on the functional uniformity of IL@MOF membranes, the nano-level control of the confined ions will be used to regulate macroscopic gas fluxes with ultrafast switching rates.
This project aims to enhance the potentials of electrochemical technologies in energy storage, in sensors and in iontronics. The benefits will not only impact the improvement of speed, quality and control in existing technologies, but it will change the way we look at mobile confined ions and launch us into new methods of using nanomaterials.
In the project, the goal is to explore the dynamic properties of nanoconfined ions by using well-defined, tunable model systems. As nanoporous host, we use thin films of metal-organic frameworks, MOFs. Ionic liquids, ILs, are used as model ions. An applied electric field will act on the nanoconfined ILs, causing its directed movements. Electrochemical impedance spectroscopy (EIS) is used to precisely measure the ionic conduction and the mobility of ions confined in the MOF thin films. By combination with Raman spectroscopy, insights in the molecular properties of the nanoconfined ions while drifting through the MOF pores are measured simultaneously to determining their mobility by EIS (Pillar 1).
The impact of the pore size, pore structure and the chemical functionalization is explored, as well as the impact of the different ILs, where the ion size of the cations and ions are tuned. (Pillar 2) First we focused on ILs with anions of different sizes in one prototype MOF host structure.
In the second goal of the project, we aim to show that nanoconfined ions provide unprecedented functionalities. The nano-level control of the confined ions will be used to regulate macroscopic gas fluxes with fast switching rates. First, we focus on the switching of the membrane permeation and selectivity of different gas molecules (Pillar 3).
The impact of the pore size, pore structure and the chemical functionalization is explored, as well as the impact of the different ILs, where the ion size of the cations and ions are tuned. (Pillar 2) First we focused on ILs with anions of different sizes in one prototype MOF host structure.
In the second goal of the project, we aim to show that nanoconfined ions provide unprecedented functionalities. The nano-level control of the confined ions will be used to regulate macroscopic gas fluxes with fast switching rates. First, we focus on the switching of the membrane permeation and selectivity of different gas molecules (Pillar 3).
Functional 2D materials like graphene possess unique electronic properties, allowing advanced devices like graphene field-effect transistors (GFETs). The combination with other advanced materials can tremendously enhance the functionality. Although the combination with functional materials like nanoporous MOFs is highly promising, the synthesis of MOFs directly on a GFET had not yet been presented. In our work (A. Chandresh, C. Wöll, L. Heinke, Adv. Funct. Mater. (2023) 2211880), for the first time, polyaromatic hydrocarbons were used to enable the controlled growth of a MOF film directly on a GFET. The MOF films grow in a homogenous, crystalline way and the electronic properties of the GFET are not impeded by the MOF-functionalization. In addition, the pores of the MOF can be filled with ILs, making a hard, solid-state ion-gated FET, which can be operated in a low-voltage, energy-saving manner. Thus, this work is also the first presentation of an ion-gated FET based on MOFs. This is realized by the direct MOF-graphene interface enabled by the presented method. Moreover, we display the sensing performance of the IL@MOF-GEFT device and find a selective sensor response.