A Covalent Organic Framework for Fast-Charge and Durable Rechargeable Mg Storage

• Published in: Nano letters Vol. 20; no. 5; pp. 3880 - 3888
• Main Authors: Sun, Ruimin, Hou, Singyuk, Luo, Chao, Ji, Xiao, Wang, Luning, Mai, Liqiang, Wang, Chunsheng
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 13.05.2020
• Subjects: cathode; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; fast charge; high energy density; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; MATERIALS SCIENCE; mg storage; porous covalent organic framework; Mg storage; high energy density; cathode; porous covalent organic framework; fast charge
• ISSN: 1530-6984; 1530-6992; 1530-6992
• DOI: 10.1021/acs.nanolett.0c01040

High-safety, low-cost, and high-volumetric-capacity rechargeable magnesium batteries (RMBs) are promising alternatives to lithium ion batteries. However, lack of high-power, high-energy, and stable cathodes for RMBs hinders their commercialization. Herein, an environmentally benign, low-cost, and sustainable covalent organic framework (COF) cathode for Mg storage is reported for the first time. It delivers a high power density of 2.8 kW kg–1, a high specific energy density of 146 Wh kg–1, and an ultralong cycle life of 3000 cycles with a very slow capacity decay rate of 0.0196% per cycle, representing one of the best cathodes to date. The comprehensive electrochemical analysis proves that triazine ring sites in the COF are redox centers for reversible reaction with magnesium ions, and the ultrafast reaction kinetics are mainly attributed to pseudocapacitive behavior. The high-rate Mg storage of the COF offers new opportunities for the development of ultrastable and fast-charge RMBs.