Ebrahim Asmaa, Ghali Mohsen, El-Moneim A A
School of Basic and Applied Science, Egypt-Japan University of Science and Technology, New Borg El Arab City, Alexandria, 21934, Egypt.
Graphene Center of Excellence for Energy and Electronic Applications, Egypt-Japan University of Science and Technology, New Borg El Arab City, Alexandria, 21934, Egypt.
Sci Rep. 2024 Jun 6;14(1):13067. doi: 10.1038/s41598-024-62317-3.
In the area of energy storage and conversion, Metal-Organic Frameworks (MOFs) are receiving more and more attention. They combine organic nature with long-range order and low thermal conductivity, giving them qualities to be potentially attractive for thermoelectric applications. To make the framework electrically conductive so far, thermoelectricity in this class of materials requires infiltration by outside conductive guest molecules. In this study, an in-situ polymerization of conductive polyaniline inside the porous structure of MOF-801 was conducted to synthesize PANi@MOF-801 nanocomposites for thermoelectrical applications. The growth of polyaniline chains of different loadings inside the host MOF matrix generally enhanced bulk electrical conductivity by about 6 orders of magnitude, leading to Seebeck coefficient value of -141 µVK and improved thermal stability. The unusual increase in electrical conductivity was attributed to the formation of highly oriented conductive PANi chains inside the MOF pores, besides host-guest physical interaction, while the Seebeck coefficient enhancement was because of the energy filtering effect of the developed structure. Modulating the composition of PANi@MOF-801 composites by varying the aniline: MOF-801 ratio in the synthesis bath from 2:1 and 1:1 to 1:2 leads to a change in the semiconductor properties from p-type semiconductor to n-type. Among the examined composites with n-type semiconducting properties exhibited the highest ZT value, 0.015, and lowest thermal conductivity, 0.24 Wm K. The synthesized composites have better performance than those recently reported for a similar category of thermoelectric materials related to MOF-based composites.
在能量存储和转换领域，金属有机框架材料（MOFs）正受到越来越多的关注。它们兼具有机特性、长程有序性和低导热性，使其在热电应用方面具有潜在吸引力。迄今为止，为使这类材料具有导电性，热电性能需要通过外部导电客体分子渗透来实现。在本研究中，通过在MOF - 801的多孔结构内原位聚合导电聚苯胺，合成了用于热电应用的PANi@MOF - 801纳米复合材料。主体MOF基质内不同负载量的聚苯胺链生长通常使整体电导率提高约6个数量级，导致塞贝克系数值为 - 141 μVK，并提高了热稳定性。电导率的异常增加归因于MOF孔内形成了高度取向的导电聚苯胺链，以及主体 - 客体物理相互作用，而塞贝克系数的提高是由于所形成结构的能量过滤效应。通过将合成浴中苯胺与MOF - 801的比例从2:1、1:1变化到1:2来调节PANi@MOF - 801复合材料的组成，会导致半导体性质从p型半导体转变为n型。在所研究的具有n型半导体性质的复合材料中，表现出最高的ZT值0.015和最低的热导率0.24 Wm⁻¹K⁻¹。合成的复合材料比最近报道的类似基于MOF的复合材料类别的热电材料具有更好的性能。
