Triphenylamine-Based Metal–Organic Frameworks as Cathode Materials in Lithium-Ion Batteries with Coexistence of Redox Active Sites, High Working Voltage, and High Rate Stability

• Published in: ACS applied materials & interfaces 2016-06, Vol.8 (23), p.14578-14585
• Main Authors: Peng, Zhe, Yi, Xiaohui, Liu, Zixuan, Shang, Jie, Wang, Deyu
• Format: Article
• Language: English
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.6b03418

Through rational organization of two redox active building block, a triphenylamine-based metal–organic framework (MOF) material, Cu-TCA (H3TCA = tricarboxytriphenyl amine), was synthesized and applied as a cathode active material for the first time in lithium batteries. Cu-TCA exhibited redox activity both in the metal clusters (Cu+/Cu2+) and organic ligand radicals (N/N+) with separated voltage plateaus and a high working potential vs Li/Li+ up to 4.3 V, comparing with the current commercial LiCoO2 cathode materials. The electrochemical behaviors of this MOF electrode material at different states of charge were carefully studied by cyclic voltammetry, X-ray photoelectron spectroscopy, and photoluminescence techniques. Long cycling stability of this MOF was achieved with an average Coulombic efficiency of 96.5% for 200 cycles at a 2 C rate. Discussing the electrochemical performances on the basis of capacity contributions from the metal clusters (Cu+/Cu2+) and organic ligands (N/N+) proposes an alternative mechanism of capacity loss for the MOF materials used in lithium batteries. This improved understanding will shed light on the designing principle of MOF-based cathode materials for their practical application in battery sciences.