Lu Jiadan, Duan Huiyu, Zhang Yi, Zhang Guangxun, Chen Zixia, Song Yongzhen, Zhu Rongmei, Pang Huan
School of Chemistry and Chemical Engineering, Institute for Innovative Materials and Energy, Yangzhou University, Yangzhou 225009, Jiangsu, P. R. China.
ACS Appl Mater Interfaces. 2022 Jun 8;14(22):25878-25885. doi: 10.1021/acsami.2c02268. Epub 2022 May 26.
Metal-organic frameworks (MOFs) are promising electrochemical materials that possess large specific surface areas, high porosities, good adjustability, and high activities. However, many conventional MOFs exhibit poor conductivity, which hinders their application in electrochemistry. In recent years, conductive MOFs (cMOFs) have attracted a considerable attention. As an important transition metal hydroxide, Ni(OH) nanosheets exhibit a high theoretical specific capacitance and a high energy density but a poor electrical conductivity. In this study, we combined a typical cMOF(Ni-HHTP, HHTP = 2,3,6,7,10,11-hexahydroxybenzene) with Ni(OH) nanosheets and synthesized a series of Ni-HHTP@Ni(OH) nanoarrays. The composite materials exhibit a high electrical conductivity and ionic transfer efficiency and a good stability. Most importantly, our study reveals the chemical interaction between cMOFs and metal hydroxide composites and the relationship between facet exposure and the growth orientation of cMOFs. When Ni-HHTP@Ni(OH)-2 was assembled as a positive electrode material in an aqueous asymmetric supercapacitor, 98% of the initial capacitance was maintained after 5000 cycles at a high current density of 3 A g. The findings of this study will provide meaningful insights into the design of cMOF composites combining other metal hydroxides.
金属有机框架材料（MOFs）是一类很有前景的电化学材料，具有大的比表面积、高孔隙率、良好的可调节性和高活性。然而，许多传统的MOFs表现出较差的导电性，这阻碍了它们在电化学中的应用。近年来，导电MOFs（cMOFs）引起了广泛关注。作为一种重要的过渡金属氢氧化物，氢氧化镍纳米片具有较高的理论比电容和能量密度，但导电性较差。在本研究中，我们将一种典型的cMOF（Ni-HHTP，HHTP = 2,3,6,7,10,11-六羟基苯）与氢氧化镍纳米片相结合，合成了一系列Ni-HHTP@Ni(OH)纳米阵列。这些复合材料具有高导电性、离子转移效率和良好的稳定性。最重要的是，我们的研究揭示了cMOFs与金属氢氧化物复合材料之间的化学相互作用以及cMOFs的晶面暴露与生长取向之间的关系。当将Ni-HHTP@Ni(OH)-2组装成水系不对称超级电容器的正极材料时，在3 A g的高电流密度下循环5000次后，初始电容保持了98%。本研究的结果将为结合其他金属氢氧化物的cMOF复合材料的设计提供有意义的见解。
