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    EXC 3120 BlueMat - Research Topic D1: Energy Storage in Supercapacitors
    We will create advanced electrochemical double-layer capacitors (EDLCs) using environmentally friendly materials and aqueous electrolytes. These supercapacitors, known for their rapid charging rates, high power density, and long cycle life, demand high-performance electrolytes and electrode materials. To prevent electrolyte decomposition, we will study high-concentration water-in-salt solutions and strong confinement. A combination of electrochemical studies, advanced in-situ/in-operando techniques, and molecular modeling will help us to understand the hydration/dehydration processes and ion transport dynamics, which are crucial for forming and structuring the EDL. Additionally, we introduce the consideration of the role of strong confinement on the electrolyte dielectric properties and optimize the microstructure of nanoporous carbons and clay-carbon composites to achieve highly energy-dense supercapacitors. Key scientific questions include: How does ion hydration influence EDL structure? Is there a specific dehydration mechanism for ions? How can ion-ion interactions be tuned, and how do they affect EDL formation? What is the impact of carbon porosity on the performance of waterin- salt electrolytes in EDLCs? Is there a correlation between the degree of carbon graphitization and EDL structure? How do the dielectric properties water and electrolyte solutions change with strong confinement in natural 2D materials?
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    EXC 3120 BlueMat - Research Topic C1: Tunable Microwave and MIR Permittivity by Control of Water Distribution
    The nanoporous structures considered in BlueMat are orders of magnitude smaller than the wavelength of microwave and MIR radiation. Thus, we will utilize water-driven materials in the effective medium regime. In the microwave range, bulk water has a high permittivity of 80, attributed to the reorientation of water dipoles. The permittivity is expected to become anisotropic at interfaces, with the component orthogonal to the interface reducing to 2. Utilizing samples with anisotropic porosity, e.g., porous silica and alumina, we envisage for the first time experimentally clarifying this water anisotropy. In the MIR range, the permittivity of bulk water reduces to 2, but water is characterized by significant absorption with an attenuation length in the order of 10 ?m. We intend to employ polyolefin aerogels, which have intrinsically high transmittance in the MIR range, and add optical tunability via reversible adsorption of water on the surface of the aerogel. The key scientific questions are: How can we control the complex permittivity of water and its anisotropy by nanoconfinement? How can we utilize water and its confinement to tune the effective permittivity of nanostructured media? How can we utilize these effects to switch microwaves and thermal radiation?
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