Effects of Particle Sizes of Active Materials and Conductive Additive on the Electrochemical Performance of a Semi-Solid Flow Battery

Abstract

The semi-solid flow battery is one of the promising energy storage technologies in the future energy systems, especially for the applications that require high energy densities. Compared to the other redox flow batteries, the semi-solid flow battery provides a higher solubility of active material and relatively higher voltage window by employing the suspension of active lithium materials and conductive additive, which can offer around 5-20 times greater volumetric capacity. In this regard, its energy density is no longer limited by the solubility, but rather the allowed fraction of active lithium material solids in the flowable suspension. Some previous studies have attempted to optimize the proportion of active lithium material solids and conductive additive to balance the trade-off between the conductivity and viscosity of the suspension. However, few of them considered the influence of the particle sizes of the active lithium materials and conductive additive. Considering that the particle sizes can have significant impacts on the percolated conductive network and rheological properties of the electrolyte suspension, their effects on the performance of the semi-solid flow battery are explored in the present study. Specifically, different particle sizes of active lithium materials and conductive additive are prepared, respectively, based on the LiNi0.8Co0.1Mn0.1O2 (LNCM)-based suspensions for the semi-solid flow battery. The resistance and electrochemical performance, as well as the rheological properties are investigated through single-cell experiments. Furthermore, the stabilities of the suspension with varying particle sizes are also investigated in the present study.