Jeffrey A. Kowalski

TL;DR: In this article, the authors investigated electrochemical systems capable of economically storing energy for hours and presented an analysis of the relationships among technological performance characteristics, component cost factors, and system price for established and conceptual aqueous and nonaqueous batteries.

TL;DR: In this article, the rational design of organic molecules with flow cell engineering was combined to boost the performance of non-aqueous redox flow batteries (NAqRFBs) for grid energy storage, achieving a current density of 100 mA cm−2 with undetectable capacity fade over 100 cycles.

TL;DR: In this article, a new heterocyclic organic anolyte molecule, 2,1,3-benzothiadiazole, has been reported, which has high solubility, a low redox potential, and fast electrochemical kinetics.

Abstract: Cost-effective electrochemical energy storage will play a critical role as society transitions to a sustainable energy economy. Nonaqueous flow batteries employing redox active organic molecules are an emerging energy storage concept. A key advantage of this device over the more established aqueous flow battery is the promise for higher cell potentials (>3 V), enabled by the larger electrochemical stability windows of nonaqueous electrolytes. Additionally, nonaqueous flow batteries could leverage new redox couples that are incompatible with aqueous electrolytes due to low solubility, chemical reactivity, and redox potentials outside of the aqueous stability window. Taking advantage of these characteristics may lead to higher energy densities, smaller system footprints, and lower costs. This mini review summarizes recent developments in all-organic nonaqueous chemistries with a focus on tailoring organic molecules for improved physical and electrochemical properties. Key opportunities and challenges in the science and engineering of these devices are presented with a goal of meeting stringent grid cost targets.

TL;DR: In this article, a simple modification of N-ethylphenothiazine, which is only stable as a radical cation (not as a dication), was reported, and it was shown that introducing electron-donating methoxy groups to nitrogen leads to dramatically improved stability of the doubly oxidized (dication) state.