Redox Flow Batteries: Fundamentals and Applications

Abstract

A redox flow battery is an electrochemical energy storage device that converts chemical energy into electrical energy through reversible oxidation and reduction of working fluids. The concept was initially conceived in 1970s. Clean and sustainable energy supplied from renewable sources in future requires efficient, reliable and cost-effective energy storage systems. Due to the flexibility in system design and competence in scaling cost, redox flow batteries are promising in stationary storage of energy from intermittent sources such as solar and wind. This chapter covers basic principles of electrochemistry in redox flow batteries and provides an overview of status and future challenges. Recent progress in redox couples, membranes and electrode materials will be discussed. New demonstration and commercial development will be addressed.

Vanadium Redox Flow Batteries: Electrochemical Engineering

“…The vanadium redox flow battery is one of the most promising secondary batteries as a large-capacity energy storage device for storing renewable energy [1,2,4]. Recently, a safety issue has been arisen by frequent fire accident of a largecapacity energy storage system (ESS) using a lithium ion battery.…”

Battery Energy Storage Systems in the United Kingdom: A Review of Current State-of-the-Art and Future Applications

“…The concept of redox flow Li-ion battery (RFLB) has been addressed in several publications as a solution to low energy density. Combining the safety and flexibility of the redox flow batteries and the high energy density of Li-ion batteries, RFLB can potentially improve the energy density of redox flow batteries by more than 10 times [60,61]. More recently, various implementations of RFLBs have been proposed: in [62], the authors describe an RFLB which stores energy in Li-ion battery materials while operating as a redox flow battery.…”

Toward High‐Voltage, Energy‐Dense, and Durable Aqueous Organic Redox Flow Batteries: Role of the Supporting Electrolytes

“…Many non‐aqueous solvents can sustain up to 6–8 V, while water has a thermodynamic potential window of only 1.23 V (Figure ) . Aqueous electrolytes are widely used in numerous rechargeable batteries owing to fast ion transport, low cost and safe character . In general, the hydrogen and oxygen evolution side reactions on electrode materials can be kinetically inhibited with overpotentials.…”

“…Different from the use of concentrated liquid electrolytes in conventional configuration of RFBs in the attempt to obtain high energy storage capability, Wang et al. has introduced a new concept that uses circulated redox shuttle molecules to enable the electrochemical reactions on the current collector inside the cell, and concomitantly chemical redox reactions of statically stored energy‐dense solid active compounds in the external tanks ,,,. Many inorganic (such as I 3 − /I − , S/S 2− , S 2 2− /S 2− and [Fe(CN) 6 ] 3− /Fe(CN) 6 ] 4− ), organic compounds (hydroquinone) and organometallic compounds (ferrocene derivatives, transition metal complexes) are suitable as redox shuttle species.…”