Reversible Redox Chemistry of Azo Compounds for Sodium‐Ion Batteries

• Published in: Angewandte Chemie (International ed.) Vol. 57; no. 11; pp. 2879 - 2883
• Main Authors: Luo, Chao, Xu, Gui‐Liang, Ji, Xiao, Hou, Singyuk, Chen, Long, Wang, Fei, Jiang, Jianjun, Chen, Zonghai, Ren, Yang, Amine, Khalil, Wang, Chunsheng
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 05.03.2018; Wiley
• Edition: International ed. in English
• Subjects: Alternative energy sources; Anodes; Azo compounds; Electrochemistry; Electrode materials; Energy storage; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Lithium; Lithium-ion batteries; organic electrode materials; Reaction mechanisms; Renewable energy; Sodium; Sodium-ion batteries; Storage batteries; anodes; organic electrode materials; sodium-ion batteries; azo compounds
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.201713417

Sustainable sodium‐ion batteries (SSIBs) using renewable organic electrodes are promising alternatives to lithium‐ion batteries for the large‐scale renewable energy storage. However, the lack of high‐performance anode material impedes the development of SSIBs. Herein, we report a new type of organic anode material based on azo group for SSIBs. Azobenzene‐4,4′‐dicarboxylic acid sodium salt is used as a model to investigate the electrochemical behaviors and reaction mechanism of azo compound. It exhibits a reversible capacity of 170 mAh g−1 at 0.2C. When current density is increased to 20C, the reversible capacities of 98 mAh g−1 can be retained for 2000 cycles, demonstrating excellent cycling stability and high rate capability. The detailed characterizations reveal that azo group acts as an electrochemical active site to reversibly bond with Na+. The reversible redox chemistry between azo compound and Na ions offer opportunities for developing long‐cycle‐life and high‐rate SSIBs. SIB‐ling rivals: A new category of organic electrode material, azo compounds, exhibits one of the best performances in organic sodium‐ion batteries (SIBs). The extended π‐conjugated structure in the aromatic azo compound and strong adsorption toward Na+ ions by nitrogen atoms in the azo group enables the long cycle life and high‐rate performance of the azo compounds.