Understanding the chemistry of graphene oxide on redox flow lithium‐ion batteries with a view to enhancing the battery's high‐density storage

Abstract

The use of graphene oxide (GO) has shown potential in improving the performance of redox flow lithium‐ion batteries (RFLIBs). These types of batteries use a liquid electrolyte containing redox‐active species to store and release energy. Despite being scalable, RFLIBs face limitations, namely, low energy density of the electrolyte and reduced cycling stability of the electrodes. However, GO's unique properties, such as its high conductivity as well as large surface area, create an attractive option for enhancing the electrochemical properties of both the electrolyte and electrodes in RFLIBs. When used as an electrode, GO improves the kinetic reversibility reactions, leading to increased electrochemical activity towards redox couples. Charge transfer resistances of positive and negative reactions are reduced, leading to increased voltage energy and efficiency of lithium batteries in terms of energy usage. As redox flow batteries made of lithium ions are an established subsystem and a growing research and development field, there is potential to enhance their performance and reduce costs through the use of GO. The objective of this review is to provide an overview of the chemistry of GO as it pertains to RFLIBs use, covering topics such as its surface chemistry, functionalization, and interactions with redox‐active species, as well as its potential for enhancing high‐density storage of electricity in batteries. Specifically, it will discuss the impact of GO on redox reactions in the electrolyte, including its ability to raise the redox‐active species concentration as well as enhance their stability. The review will also examine how GO impacts the electrodes, including its potential to increase their surface area and conductivity and promote cycling stability. Additionally, the review will address the importance of optimizing the quantity and distribution of GO in both the electrolyte and electrodes of RFLIBs.