Journal Article

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

Su, Chenliang, Ng, Man-fai, Armand, Michel, Hu, Yong-sheng, Tian, Bingbing, Zu, Lianhai, Ning, Guo-hong, Yang, Jinhu, Yu, Dingyi, Zhong, Guiming, Peng, Chengxin, Tang, Wei, Su, Jie, Loh, Kian Ping, Yang, Yong

2017

Overview

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 π-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.

• Publisher: Nature Publishing Group
• Subject: Batteries / Carbonyl compounds / Carbonyls / Cathodes / Chemical synthesis / Electrical conductivity / Electrical resistivity / Electron density / Functional groups / Graphene / o-Phenylenediamine / Organic chemistry / Phenylenediamine / Pyrazine / Quinoxaline / Quinoxalines / Rechargeable batteries / Redox reactions / Specific capacity