Enhancing the Performance of Viscous Electrode-Based Flow Batteries Using Lubricant-Impregnated Surfaces

Abstract

Redox flow batteries are a promising technology that can potentially meet the large-scale grid storage needs of renewable power sources. Today, most redox flow batteries are based on aqueous solutions with low cell voltages and low energy densities that lead to significant costs from hardware and balance-of-plant. Nonaqueous electrochemical couples offer higher cell voltages and higher energy densities and can reduce system-level costs but tend toward higher viscosities and can exhibit non-Newtonian rheology that increases the power required to drive flow. This work uses lubricant-impregnated surfaces (LIS) to promote flow in electrochemical systems and outlines their design based on interfacial thermodynamics and electrochemical stability. We demonstrate up to 86% mechanical power savings at low flow rates for LIS compared to conventional surfaces for a lithium polysulfide flow electrode in a half-cell flow battery configuration. The measured specific charge capacity of ∼800 mAh/(g·S) is a 4-fold increase over previous work.