Supramolecular Interactions and Non-Equilibrium Properties of Non-Aqueous Electrolytic Solutions for Next Generation Flow Batteries

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. Further investigation of the mechanism by which viscosity increases is still undergoing. Herein, we present the simulation results and relative analysis.