Recent Progress on Organic Electrode Materials for Multivalent (Zn, Al, Mg, Ca) Secondary Batteries

Multivalent secondary batteries (MSBs) have attracted great attention in view of their rich resources, low cost, and high safety. However, its development and application are still plagued by electrode materials. With their renewable and highly adjustable structures, organic electrode materials (OEMs) have several advantages over traditional inorganic electrode materials (IEMs), which has become the current research hotspot of electrode materials for MSBs. In this review, we present the recent developments in OEMs used for secondary batteries, including carbonyl compounds, imine compounds, conductive polymers, covalent organic frameworks, organic cyanides, organosulfur polymers and so on. An overview of the structural characteristics, energy storage mechanism, and electrochemical performance of OEMs in MSBs is given. Furthermore, to reveal the reasons for the high performance of the preponderant organic electrode materials, the relationships between material structures, electrolyte system, and battery properties are discussed in detail. Finally, we hope that this review could provide a fundamental guide to developing and designing high-performance MSBs in the future.