Fast and stable cycling of 2,6-diaminoanthraquinone as a redox-active organic cathode for sodium-ion batteries

Abstract

Sodium-ion batteries (SIBs) have attracted considerable attention due to their electrochemical similarity to lithium-ion batteries. One approach to advancing the SIB system involves the use of redox-active compounds as sustainable cathode materials. Organic compounds offer the advantage of tunable electrochemical properties, which can be modulated by altering their molecular structures. In this study, the commercially available 2,6-diaminoanthraquinone (2,6-DAAQ) was investigated as a potential cathode material for SIBs. Its sodium-ion storage capabilities were investigated through a combination of electrochemical measurements and density functional theory (DFT) calculations. In addition, the insertion of two Na⁺ ions into the 2,6-DAAQ cathode was analyzed via ex situ ATR FT-IR spectroscopy. The results indicate that the carbonyl groups participate in the redox processes during charge–discharge cycling. The 2,6-DAAQ cathode also exhibited excellent cycling stability and rate capability, which can be attributed to its dominant capacitive behavior. Overall, 2,6-DAAQ demonstrated reversible sodium-ion storage, highlighting its potential as a stable organic cathode for next-generation SIBs.