Poly(1,5-diaminoanthraquinone) as a High-Capacity Bipolar Cathode for Rechargeable Magnesium Batteries

• Published in: ACS applied energy materials Vol. 5; no. 3; pp. 3004 - 3012
• Main Authors: Ding, Yiyuan, Ren, Xin, Chen, Dong, Wen, Fanjue, Li, Ting, Xu, Fei
• Format: Journal Article
• Language: English
• Published: American Chemical Society 28.03.2022
• Subjects: poly(1,5-diaminoanthraquinone); rechargeable Mg batteries; polyaniline chain; poly(1-aminoanthraquinone); conjugated carbonyl polymers
• ISSN: 2574-0962; 2574-0962
• DOI: 10.1021/acsaem.1c03652

Rechargeable Mg batteries have the advantages of abundant reserves and high safety, but suitable inorganic cathodes are quite limited. Organic polymers break the hindrance of the inorganic Mg-storage crystal lattice and provide more selections, but the reports on organic rechargeable Mg battery cathodes are relatively few. Herein, high-capacity bipolar organic cathodes are developed for rechargeable Mg batteries. Poly­(1,5-diaminoanthraquinone) with double polyaniline chains is used as a bipolar cathode. The carbonyl and amino groups are employed as the N-doping and P-doping centers, respectively, and the conjugated anthraquinone unit delocalizes the charge density change during the redox reactions. Considering the mass of Mg salt, the poly­(1,5-diaminoanthraquinone) cathode provides a high corrected capacity of 267 mA h g–1 (non-corrected capacities of 297 mA h g–1) for bipolar reactions. Moreover, compared with the single-chained poly­(1-aminoanthraquinone) (44% capacity maintained after 140 cycles), the double-chained poly­(1,5-diaminoanthraquinone) shows a much better N-doping cycleability (97% capacity maintained after 300 cycles), as the double polyaniline chains enhance the structure stability during the Mg-storage reaction. The present study demonstrates the importance of a large conjugated double-chain structure to enhance the Mg-storage performance of organic polymers. It is also imagined that the bipolar organic materials with both of N- and P-dopings are a highly promising strategy for development of high-capacity organic Mg battery cathodes.