| Autor: |
Ren, Zhou-Hong, Zhang, Zhi-Ruo, Ma, Li-Jun, Luo, Chen-Yue, Dai, Jie, Zhu, Qin-Yu |
| Zdroj: |
ACS Applied Materials & Interfaces; February 2023, Vol. 15 Issue: 5 p6621-6630, 10p |
| Abstrakt: |
Poor electrical conductivity and instability of metal–organic frameworks (MOFs) have limited their energy storage and conversion efficiency. In this work, we report the application of oxidatively doped tetrathiafulvalene (TTF)-based MOFs for high-performance electrodes in supercapatteries. Two isostructural MOFs, formulated as [M(py-TTF-py)(BPDC)]·2H2O (M = NiII(1), ZnII(2); py-TTF-py = 2,6-bis(4′-pyridyl)TTF; H2BPDC = biphenyl-4,4′-dicarboxylic acid), are crystallographically characterized. The structural analyses show that the two MOFs possess a three-dimensional 8-fold interpenetrating diamond-like topology, which is the first example for TTF-based dual-ligand MOFs. Upon iodine treatment, MOFs 1and 2are converted into oxidatively doped 1-oxand 2-oxwith high crystallinity. The electrical conductivity of 1-oxand 2-oxis significantly increased by six∼seven orders of magnitude. Benefiting from the unique structure and the pronounced development of electrical conductivity, the specific capacities reach 833.2 and 828.3 C g–1at a specific current of 1 A g–1for 1-oxand 2-ox, respectively. When used as a battery-type positrode to assemble a supercapattery, the AC∥1-oxand AC∥2-ox(AC = activated carbon) present an energy density of 90.3 and 83.0 Wh kg–1at a power density of 1.18 kW kg–1and great cycling stability with 82% of original capacity and 92% columbic efficiency retention after 10,000 cycles. Ex situ characterization illustrates the ligand-dominated mechanism in the charge/discharge processes. The excellent electrochemical performances of 1-oxand 2-oxare rarely reported for supercapatteries, illustrating that the construction of unique highly dense and robust structures of MOFs followed by postsynthetic oxidative doping is an effective approach to fabricate MOF-based electrode materials. |
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