Solid Particle Flow Battery Design and Characterization

Classic flow battery systems have consisted of transition metals dissolved in aqueous solvents which provide the electroactive materials.  These flow battery systems have relatively low energy densities due to the stability window of water limiting the operating voltage and the solubility of the transition metals limiting the practical capacity.  Recently, a few research groups have explored flow batteries with solid particles as the electroactive materials, in an effort to increase the energy density of the catholyte and anolyte materials.  Many of these reported systems have extremely high viscosities because of the high solid particle loadings in the electrolyte.  These high viscosities will result in high energy demands for the pumping of the electroactive fluids.  Our group has been working on flow battery systems that take advantage of the energy density advantages of solid particles, but with a goal of not having prohibitive parasitic energy losses from pumping these fluids through the flow battery system.  This work will describe the design and characterization of a flow battery that operates at reasonable viscosities for a particle-laden electrolyte, and the observed coupling between electrochemical properties and rheological properties in a solid particle flow battery system.