Redox flow batteries: role in modern electric power industry and comparative characteristics of the main types

Abstract

In recent years, the key principles of the electric power industry have radically changed and the number of studies on the development of devices for electrical energy storage in a different form such as mechanical or chemical energy has rapidly increased. This review gives a brief description of these devices. The attention is focused on redox flow batteries (RFBs), a promising type of energy storage devices capable of efficiently operating in distributed power grids, in order to eliminate the imbalance between the time-varying electricity production by ‘unconventional sources’ and electricity consumption. At the design level, RFBs combine the principles of fuel cells and chemical energy sources with solid electroactive materials: transitions between electrical and chemical forms of energy in these devices occur upon oxidation and reduction of redox-active electrolytes, which are stored in separate tanks and pumped into the electrode compartments of the membrane electrode assembly (MEA) separated by a semi-permeable membrane. This approach ensures an important advantage of these devices over other types of chemical energy sources, that is, the possibility of independent scaling of the energy storage capacity and power characteristics of the system. This review provides a systematic description of the main types of RFBs and analysis of their fundamental benefits and drawbacks, which determine the prospects for practical applications of RFBs. The bibliography includes 149 references.

Promising Material Based on Paraffin‐Impregnated Graphite Foil with Increased Electrochemical Stability for Bipolar Plates of Vanadium Redox Flow Battery

“…Polarization curves have a linear shape since V 2 + /V 3 + , and VO 2 + /VO 2 + redox reactions proceed with minimal activation losses even at common carbon felt electrodes and as a result, overall battery performance is dictated by cell ohmic resistance. [1] Polarization curves of cells based on the most common Nafion 117 membrane for different BP materials are practically the same since membrane resistance has the biggest contribution to overall cell resistance, and peak power density varied within 572-598 mW cm À 2 (see Table 1, and Table S1). To highlight the difference in discharge performance of cells with different BP we carried out polarization curves of the cells with thin and highly conductive Nafion 211 membrane: maximum power density for GFÀ P-2 (6.01 %) and pristine GF was the same (866, and 867 mW cm À 2 , respectively) and comparable with graphite-based cell (899 mW cm À 2 ).…”

“…Redox flow batteries (RFB) have shown outstanding promise for grid-scale energy storage due to the flexible capacity and power scaling for the consumer's needs. [1] The all-vanadium RFB (VRFB) technology is already available on the energy storage market, but its widespread implementation is limited by the high levelized cost of energy storage or LCOS (190-400 $ (MWh) À 1 , as of 2019). [2] The vanadium electrolyte accounts for a largest portion of VRFB capital cost [3].…”

“…For that reason, many efforts have been made to develop RFB based on affordable electrolytes. [1] Another possible solution is to decrease the cost of the main components of the battery. For example, there is a number of works dedicated to the development of affordable ion-exchange membranes and electrode materials.…”

“…The growing role of renewable power sources in global energy production increased the demand for effective large‐scale energy storage. Redox flow batteries (RFB) have shown outstanding promise for grid‐scale energy storage due to the flexible capacity and power scaling for the consumer's needs [1] . The all‐vanadium RFB (VRFB) technology is already available on the energy storage market, but its widespread implementation is limited by the high levelized cost of energy storage or LCOS (190–400 $ (MWh) −1 , as of 2019) [2] .…”

Two‐Membrane Acid‐Base Flow Battery with Hydrogen Electrodes for Neutralization‐to‐Electrical Energy Conversion

“…ABFBs have several unique advantages over other flow batteries, such as an ability to neutralize hazardous acidic and alkaline wastewaters while obtaining neutralization energy, low cost or even zero cost (in case of acidic and alkaline wastewaters) of electrolytes, and a high solubility and low toxicity of the electrolytes [31,32] . The main issues of ABFBs are as follows: discharge current density limitations dictated by bipolar membrane delamination issue; the strong impact of undesired ionic species transport through the ion‐exchange membranes (so‐called crossover); low real values of energy density and quite high cells internal resistance values [19] .…”