My group works in the field of soft condensed matter and statistical physics and we are particularly interested in electrolyte systems and biological modeling. We have a strong background in studying structure and ordering transitions in complex many-body systems and in the development and application of classical density functional theory (DFT).
In particular, we study
- charged colloidal and ionic particles, ionic fluids, and the build of electric double layers (EDLs), exemplary shown in Figure 1,
- active Brownian particles and biological swimmers that interact with their environment, an example for active Brownian disks is shown in Figure 3,
- hard particles and their phase transitions,
- classical density functional theory (DFT) and its applications,
- power functional theory (PFT), a full non-equilibrium time-dependent DFT formalism,
- energy storage in EDLs with impact to supercapacitive technologies like supercapacitors, capacitive mixing (Capmix) for blue-energy harvesting, and capacitive deionization (CDI) to recover and desalinate water; a model supercapacitor is shown in Figure 2;
- underscreening, overscreening, and structural transitions in EDLs,
- thermal effects like the thermal voltage rise and thermocapacitive energy conversion,
- thermodynamic cycles and new heat-to-current conversion technology,
- interfaces and phase separations, driven colloidal suspensions, clustering, nucleation, percolation,
- the physics of food preparation in the kitchen,
- and much more.
Our research is supported by the German Research Foundation (DFG) by a project on
Capacitive density functional theory for
structure and screening in ionic fluids and electric double layers
with applications in sustainability.
Project description via gepris.dfg.de
Figure 1. Sketch of an electric double layer (EDL). A positively charged flat electrode is in contact with an electrolyte solution, where the mobile ionic charges arrange themselves to screen the charges on the electrode. One can distinguish between a close layer of counter ions (Helmholtz layer) and a diffuse layer.
Figure 2. Sketch of multi-scale supercapacitor model. Typical length scales are (from the left to the right) 0.3 nm particle size, 1-10 nm pore width, 1 mm electrode size.
Figure 3. Snapshot of a system of active Brownian disks. The magnification window shows structures that originate form the disk's activity.
© A. Härtel (2023)