Demonstration of Carbon-Free Lithium-Ion Redox Flow Couple

Abstract

Redox flow batteries have been actively researched in part because of the key advantage to independently design and adjust the power and energy of the system. The most common redox flow batteries are transition metals dissolved in aqueous solvent, and these batteries have energy density limitations caused by the solubility of the active species in the electrolyte. Semi-solid flow batteries have recently been reported as an alternative, where high energy density was achieved by incorporation of lithium-ion active material solid particles as the energy storage media accompanied with carbon additives to provide a conductive network. A challenge with these semi-solid flow batteries is the high viscosity of the flowing slurry, which results from the interconnected carbon network. In this presentation, we will describe a new type of flow battery comprised of flowing suspensions of carbon-free lithium-ion active materials in the electrolyte. The electrochemical reactions occur during collisions of active material particles with the current collectors. We will demonstrate proof-of-concept for both half-cells and full-cells in custom geometries using multiple electrochemical testing techniques.