Stable Hexaazatrinaphthalene-Based\nPlanar Polymer\nCathode Material for Organic Lithium-Ion Batteries

Abstract

Organic materials have garnered intensive focus as a\nnew group\nof electrodes for lithium-ion batteries (LIBs). However, many reported\norganic electrodes so far still exhibit unsatisfying cycling stability\nbecause of the dissolution in the electrolytes. Herein, a novel azo-linked\nhexaazatrianphthalene (HATN)-based polymer (AZO-HATN-AQ) is designed\nand fabricated by the polymerization of trinitrodiquinoxalino[2,3-a:2′,3′-c]phenazine\n(HATNTN) and 2,6-diaminoanthraquinone (DAAQ). The abundant redox-active\nsites, extended π-conjugated planar conformation, and low energy\ngap endow the AZO-HATN-AQ electrode with high theoretical capacity,\nexcellent solubility resistance, and fast Li-ion transport. In particular,\nthe fully lithiated AZO-HATN-AQ still keeps the planar structure,\ncontributing to the excellent cycling stability. As a result, AZO-HATN-AQ\ncathodes show high specific capacity (240 mAh g^–1 at 0.05 A g^–1), prominent rate capability (98\nmAh g^–1 at 8 A g^–1), and outstanding\ncycling stability (120 mAh g^–1 after 2000 cycles\nat 4 A g^–1 with 85.7% capacity retention) simultaneously.\nThis study demonstrates that rational structure design of the polymer\nelectrodes is an effective approach to achieving excellent comprehensive\nelectrochemical performance.