Intermediate-Range Interactions and Non-Equilibrium Properties of Non-Aqueous Electrolytic Solutions for Next Generation Flow Batteries
Abstract: Batteries and energy storage is one of the five DOE Energy Innovation Hubs that combine basic and applied research with engineering to accelerate scientific discovery and address critical energy issues. Future battery technologies for transportation and grid applications are receiving huge interest due to their importance in reducing energy loss due to the non-load following nature of the current energy generation sources, and achieving a more green environment with the reduction of oil consumption in transportation.
Today’s batteries meet only some of their targeted performance metrics. Meeting all of the targeted performance metrics for a given application requires new materials with transformative behavior, such as simultaneously achieving high reactivity, high mobility and high stability in electrodes. Such transformative materials are not readily available in nature. They must be designed based on an intimate knowledge of the atomic and molecular origins of the targeted behavior.
Non-aqueous electrolytes enable batteries to operate at higher cell potentials compared to its aqueous counterpart due to the wider electrochemical stability window of the former. Super-concentrated electrolytic solutions are emerging as a new class of liquid electrolytes with various unusual functionalities beneficial for advanced Li battery applications. However, a desired high ionic conductivity is missing in the high-concentrated regime due to a reduction in ionic mobility. Reduced ionic motility is ascribed to an increase in solution viscosity whose mechanism is still not fully understood. We hypothesize that we could tune the solution viscosity via modulating the supramolecular interactions enabling a groundbreaking solution for fast recharging rate of these batteries. We carried out MD simulations to investigate the mechanism by which the ionic conductivity decreases. We first observed a reduction in the number free-ion carriers via formation of contact ion pair in this high concentration regime. Moreover, we found, from a viscoelastic framework perspective, the rigidity of the emergent medium-range order structures plays a role in understanding the slower dynamics in the concentrated regime of some electrolytic solutions. Herein, we present the simulation results and relative analysis.
Bio: Graduate Research Assistant in Z lab, at Nuclear, Plasma, and Radiological Engineering (NPRE), University of Illinois Urbana-Champaign. Interested in understanding the fundamental principles underlying the collective behavior and emergent character of disordered condensed matter, namely liquids, under extreme /interfacial /non-equilibrium conditions, using integrated theory-driven atomistic simulations and neutron and X-ray experiments. Faithful to the crucial role of volunteering in changing and reshaping current circumstances with limited resources seeking a better world. Throughout the undergraduate period in his home country, Egypt, Hossam served as a volunteer and board-member of the world first IEEE Nuclear and Plasma Sciences Society student chapter.
Currently pursuing a Master's degree in NPRE. Master’s thesis addresses the structure and dynamics of the solution phase of non-aqueous electrolytes for next–generation flow–batteries. The work is funded under DOE’s JCESR project. The thesis work can be summarized in the following:
- Refinement of the Born–Oppenheimer potential energy surface of novel synthesized molecules, using NWCHEM quantum chemistry package, leading to more accurate electronic coarse–grained models.
- Molecular Dynamics simulations of model non-aqueous electrolytic solutions, using GROMACS toolkit, to investigate their charge, mass, and momentum transport, and benchmarked against experimental x-ray scattering spectra, conductivity, and diffusivity measurements.
- Extension of understanding of novel molecules’ ionic mobility across a wide range of concentration regimes in relation to their equilibrium solvation environment and supramolecular emergent structures using the infinite-frequency shear modulus as a newly proposed descriptor of the “rigidity or softness” of the formed supramolecular structures in-solution
By pursuing graduate studies, I hope to deepen my understanding of the fundamental principles underlying the field of my interest, to get exposed to the state-of-the-art techniques employed in current cutting-edge research; paving the way to fit as a research scientist in a prestigious research institute.
