Organic Compound as a Cathode for Aqueous Zinc-Ion Batteries with Improved Electrochemical Performance via Multiple Active Centers
Lulu Huang, Jiahao Li, Jiali Wang, Heng Lv, Yanyan Liu, Banghua Peng, Long Chen, Wen Guo, Gang Wang, Tiantian Gu
Abstract
Aqueous zinc-ion batteries (AZIBs) are deemed as an emerging substitute for secondary batteries. The type of cathode material has enormous implications for the performance of AZIBs. Organics can act as a suitable cathode for AZIBs because of their green, adjustable structure and good stability. However, developing promising organics with high performance is still an important challenge. Here, an organic material 8,21-dihydronaphtho[2,3-a]naphtha[2′,3′:7,8]quinoxalino[2,3-i]phenazine-5,11,16,22-tetraone (DADB) was synthesized and explored as a cathode for AZIBs. Benefiting from the affluent active sites and the expanded conjugated structure, the DADB electrode rendered splendid rate capability (71 mA h g–1 under 5 A g–1) and outstanding cycle lifespan (87% retention over 6000 cycles under 10 A g–1). Moreover, ex situ characterizations proved that C═N and C═O bonds were the electrochemical redox centers for storage of Zn2+. Additionally, the DADB electrode also exhibited excellent electrochemical performance in a gel electrolyte (134 mA h g–1 under 0.05 A g–1). This research offered a mentality for designing high-performance organic cathodes of AZIBs.