Organic Compound\nas a Cathode for Aqueous Zinc-Ion\nBatteries with Improved Electrochemical Performance via Multiple Active\nCenters

Abstract

Aqueous zinc-ion batteries (AZIBs) are deemed as an emerging\nsubstitute\nfor secondary batteries. The type of cathode material has enormous\nimplications for the performance of AZIBs. Organics can act as a suitable\ncathode for AZIBs because of their green, adjustable structure and\ngood stability. However, developing promising organics with high performance\nis still an important challenge. Here, an organic material 8,21-dihydronaphtho­[2,3-<i>a</i>]­naphtha­[2′,3′:7,8]­quinoxalino­[2,3-<i>i</i>]­phenazine-5,11,16,22-tetraone (DADB) was synthesized and\nexplored as a cathode for AZIBs. Benefiting from the affluent active\nsites and the expanded conjugated structure, the DADB electrode rendered\nsplendid rate capability (71 mA h g^–1 under 5 A\ng^–1) and outstanding cycle lifespan (87% retention\nover 6000 cycles under 10 A g^–1). Moreover, ex situ\ncharacterizations proved that CN and CO bonds were\nthe electrochemical redox centers for storage of Zn²⁺.\nAdditionally, the DADB electrode also exhibited excellent electrochemical\nperformance in a gel electrolyte (134 mA h g^–1 under\n0.05 A g^–1). This research offered a mentality for\ndesigning high-performance organic cathodes of AZIBs.