Progress of organic, inorganic redox flow battery and mechanism of electrode reaction

Abstract

With the deployment of renewable energy and the increasing demand for power grid modernization, redox flow battery has attracted a lot of research interest in recent years. Among the available energy storage technologies, the redox flow battery is considered the most promising candidate battery due to its unlimited capacity, design flexibility, and safety. In this review, we summarize the latest progress and improvement strategies of common inorganic redox flow batteries, such as vanadium redox flow batteries, iron-chromium redox flow batteries, and zinc-based redox flow batteries, including electrolyte, membrane, electrode, structure design, etc. In addition, we introduce the latest progress in aqueous and nonaqueous organic redox flow batteries. We also focus on the modification mechanism, optimization design, improvement strategy, and modeling method of the redox flow battery reaction. Finally, this review presents a brief summary, challenges, and perspectives of the redox flow battery.

The Effect of Electrolyte Composition on the Performance of a Single‐Cell Iron–Chromium Flow Battery

“…[1,23] One of the main causes of CE losses, specifically in the ICRFB, is due to H 2 production (hydrogen evolution reaction -Equation ( 2)), which is a parasitic side reaction on the negative electrode that irreversibly consumes charging current leading to a reduced CE. [13][14][15][16]…”

“…[3] Both the active species (type, concentration, and ratio) and the supporting electrolyte (type and concentration) influence the overall RFB performance. [13] Where the electroactive species stores or supplies energy during charge and discharge cycling by undergoing oxidation and reduction reactions, [4,14] the supporting electrolyte influences the conductivity and the stability of the redox reactions. [14,15] Where the active species concentration is directly proportional to the battery's storage capacity, the supporting electrolyte concentration is inversely proportional to the areaspecific resistance (ASR) and thus the voltage efficiency.…”

Regulating Protons to Tailor the Enol Conversion of Quinone for High-Performance Aqueous Zinc Batteries

“…The heterogeneous enolization reaction in carbonyl redox chemistry between CO and C–O – is an essential physiological process in organisms that widely exist in nature. , It sheds light on the broad utilization of organic carbonyl-based aqueous organic electrode materials, where the electrochemical performance could be regulated by tailoring the structure and functional groups of the carbonyls. − Specifically, due to the high theoretical capacity and fast reaction kinetics, the carbonyl-based organics with small molecular weights are the widely studied cathodes for high-performance aqueous energy storage, especially when coupled with the Zn metal anode. − However, the low energy density and the poor cycling stability make the overall electrochemical performance of these carbonyl-based organic electrodes still not comparable with the inorganic counterparts. , To solve this problem, various strategies have been adopted to modify the carbonyl-based electrodes, such as hybridization with carbon materials, molecular polymerization, functional group manipulation, , and constructing the conjugate structure. , Although the electrochemical performance of the organic electrodes has been accordingly improved to a certain extent, the corresponding synthesis complexity, high costs, and more nonactive components might make their practical application more difficult. − Recently, the electrochemical behaviors of the organic electrodes were revealed to be differentiated when storing different charge carriers in electrolytes. , It shed light on electrolyte engineering by adjusting the components in the electrolyte, which could accommodate more simplicity and efficiency in performance improvement compared with the complex electrode modifications . Thus, it can potentially improve the performance of organic electrode materials by tailoring ion species being stored by the carbonyl electrodes, while clarifying the charge storage manners of organic materials is a prerequisite.…”

Multifunctional Carbon Nanodots for Antibacterial Enhancement, pH Change, and Poisonous Tin(IV) Specifical Detection

“…Sn poisoning can also cause serious damage to liver function and nervous system. In the last two decades, with the continuous development of industry, the use and consumption of tin have been increasing annually in many fields, including electronics, information, electrical appliances, chemical industry, metallurgy, and food packaging. − However, Sn poisoning has received limited attention worldwide, with relatively few corresponding detection probes and methods. Liu et al synthesized a fluorescent sensor, 1,4-bis­(2-(quinoline-8-epoxy) acetyl) pyrazine (DQS), which had sensing ability to Sn 4+ within the pH range of 4–10 .…”