Synergetic coupling of hydrogen-bond bridge and multielectron redox towards stable and efficient lithium storage

Abstract

The flexible molecular engineering has been emerged as a viable option for constructing the high-performance organic cathodes. Herein, a unique crystalline organic supramolecular structure of hexaazatrinaphthalene tricarboxylic acid (denoted as HOS-HATNTA) is engineered by constructing a hydrogen-bonded bridge between the organic ligands, which features to couple the synergetic effects of stable network structure and multiple paths for electron redox. Not only does the bridge serve as a stable channel to allow triggering a chain of similar displacements for transporting ions, but the bridge itself also play an important role in boosting the electron transfer between the pyrazine N in different layers, which enables the efficient lithium storage. As a result, HOS-HATNTA cathode exhibits an all-round elevation of electrochemical metrics including the large specific capacity (271.6 mAh g−1 at 50 mA g−1), large-current tolerance (144.3 mAh g−1 at 5 A g−1), and the impressive long-life span (> 3000 cycles at 3 A g−1). Mechanistic studies encompassing XPS, in-situ Raman, kinetic analyses and DFT calculations comprehensively reveals the multiple mechanism of hydrogen bond supramolecule network in electrochemical behaviors for LIBs, which bring a promising insight into engineering high performance organic cathode materials.