The electric conductivity and charge transport efficiency of metal–organic frameworks (MOFs) dictate the effective utilization of built-in redox centers and electrochemical redox kinetics and therefore electrochemical performance. Reticular chemistry and the tunable microcosmic shape of MOFs allow for improving their electric conductivity and charge transfer efficiency. Herein, we synthesized two Ni-MOFs (Ni-tdc-bpy and Ni-tdc-bpe) by the solvothermal reaction of Ni²⁺ ions with 2,5-thiophenedicarboxylic acid (H₂tdc) in the presence of conjugated 4,4′-bipyridyl (bpy) and 1,2-di(4-pyridyl)ethylene (bpe) coligands, respectively. We also synthesized two thinning Ni-MOFs (Ni-tdc-bpy(0.5) and Ni-tdc-bpe(0.5)) by adjusting the amounts of bpy and bpe, respectively. Experimental investigations revealed that linker engineering by tuning the delocalization of the N-donor dipyridyl coligands and size optimization by controlling the amount of the coligand rendered the Ni-MOF with significantly improved electrical conductivity and charge transport efficiency. Among them, Ni-tdc-bpe(0.5) possessing the bpe coligand with more strong delocalization and an optimized size exhibited an enhanced specific capacitance of 650 F g^–1 at 0.5 A g^–1. Moreover, the hybrid supercapacitor constructed from Ni-tdc-bpe(0.5) and activated carbon delivered an excellent energy density of 33.6 Wh kg^–1 at a power density of 232.6 W kg^–1.

中文翻译：

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增强金属-有机框架的电化学储能：连接子工程和尺寸优化


金属有机框架 （MOF） 的电导率和电荷传输效率决定了内置氧化还原中心和电化学氧化还原动力学的有效利用，从而决定了电化学性能。MOF 的网状化学和可调微观形状可以提高其导电性和电荷转移效率。在此，我们通过 Ni²⁺ 离子与 2,5-噻吩二羧酸 （H₂tdc） 在共轭 4,4′-联吡啶基 （bpy） 和 1,2-二（4-吡啶基）乙烯 （bpe） 配体存在下进行溶剂热反应合成了两种 Ni-MOF（Ni-tdc-bpy 和 Ni-tdc-bpe）。我们还通过分别调整 bpy 和 bpe 的量合成了两种减薄的 Ni-MOFs（Ni-tdc-bpy（0.5） 和 Ni-tdc-bpe（0.5））。实验研究表明，通过调整 N 供体二吡啶基配体的离域和通过控制配体数量来优化尺寸，使 Ni-MOF 具有显着提高的电导率和电荷传输效率。其中，Ni-tdc-bpe（0.5） 具有更强离域和优化尺寸的 bpe 配体，在 0.5 A g^–1 时表现出 650 F g^–1 的增强比电容。此外，由 Ni-tdc-bpe（0.5） 和活性炭构成的混合超级电容器在 232.6 W ^kg-1 的功率密度下提供了 33.6 Wh ^kg-1 的出色能量密度。