Understanding the Sodium Storage Mechanisms of Organic Electrodes in Sodium Ion Batteries: Issues and Solutions

Organic electrode materials offer new opportunity to develop high energy/power density, low cost, environmentally benign sodium ion batteries (SIBs). For many years this category of materials has not been considered as a potential electrode candidate for SIBs, mainly because, the excessive research was focusing on the inorganic materials, due to the successful commercialization of the same category of materials in the proven lithium ion battery (LIB) technologies. However, recently many promising advancements have been made in the field of organic cathode and anode materials for SIB applications. This review for the first time consolidates and provides insights into the different sodium storage mechanisms that are observed in various categories of organic electrode materials. We believe that the fundamental understanding of redox mechanisms, that governs the electrochemical performances of SIBs, are very necessary to design new materials/electrodes, as well as is beneficial for enhancing the existing properties of the investigated compounds.