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Reversible multi-electron redox chemistry of pi-conjugated N-containing heteroaromatic molecule-based organic cathodes

TitleReversible multi-electron redox chemistry of pi-conjugated N-containing heteroaromatic molecule-based organic cathodes
Publication TypeJournal Article
Year of Publication2017
AuthorsPeng, Chengxin, Ning Guo-Hong, Su Jie, Zhong Guiming, Tang Wei, Tian Bingbing, Su Chenliang, Yu Dingyi, Zu Lianhai, Yang Jinhu, Ng Man-Fai, Hu Yong-Sheng, Yang Yong, Armand Michel, and Loh Kian Ping
JournalNat. Energy
Volume2
Pagination17074
Date Published07/2017
ISSN2058-7546
Keywordsbasis-sets, flow battery, high-energy density, lithium-ion batteries, low-cost, orbital methods, polymer electrolyte, ray photoelectron-spectroscopy, rechargeable batteries, storage materials
Abstract

Even though organic molecules with well-designed functional groups can be programmed to have high electron density per unit mass, their poor electrical conductivity and low cycle stability limit their applications in batteries. Here we report a facile synthesis of pi-conjugated quinoxaline-based heteroaromatic molecules (3Q) by condensation of cyclic carbonyl molecules with o-phenylenediamine. 3Q features a number of electron-deficient pyrazine sites, where multiple redox reactions take place. When hybridized with graphene and coupled with an ether-based electrolyte, an organic cathode based on 3Q molecules displays a discharge capacity of 395 mAh g(-1) at 400 mA g(-1) (1C) in the voltage range of 1.2-3.9 V and a nearly 70% capacity retention after 10,000 cycles at 8 A g(-1). It also exhibits a capacity of 222 mAh g(-1) at 20C, which corresponds to 60% of the initial specific capacity. Our results offer evidence that heteroaromatic molecules with multiple redox sites are promising in developing high-energy-density, long-cycle-life organic rechargeable batteries.

DOI10.1038/nenergy.2017.74

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