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Microwave-assisted synthesis of a manganese metal–organic framework and its transformation to porous MnO/carbon nanocomposite utilized as a shuttle suppressing layer in lithium–sulfur batteries

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Abstract

In this work, the microwave-assisted synthesis of manganese metal–organic framework (MOF) material is presented. Synthesis procedure is based on a microwave-assisted solvothermal reaction of manganese(III) acetylacetonate with biphenyl-4,4′-dicarboxylic acid (Bpdc) in N,N′-dimethylformamide at the temperature of 160 °C. The obtained Mn-based metal–organic framework, labeled as Mn-Bpdc, was used as a precursor for the preparation of a porous MnO/carbon nanocomposite, which was obtained via thermal transformation in a nitrogen atmosphere at 700 °C. It was found that this approach provides an effective and simple preparation pathway for porous carbon decorated with homogeneously embedded manganese(II) oxide nanoparticles. Both Mn-Bpdc and MnO/C nanocomposite materials were characterized by a variety of physicochemical methods. The prepared MnO/C nanocomposite material was deposited on a cathode surface of lithium-sulfur batteries and utilized as a shuttle suppressing layer. This electrode structure immobilizes polysulfides inside the cathode and improves the stability during cycling. The electrode with MnO/C nanocomposite shuttle suppressing layer maintains high stability during cycling in comparison with a standard electrode. The electrode with MnO/C composite layer exhibits 84.8% capacity retention after 50 cycles at different C-rates compared to 76.2% obtained for the standard electrode.

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Acknowledgements

This work was supported by the Ministry of Education, Youth and Sports of the Czech Republic - Program NPU I (LO1504) and (LO1210). This contribution was written with support of Operational Program Research and Development for Innovations co-funded by the European Regional Development Fund (ERDF) and national budget of Czech Republic, within the framework of project CPS - strengthening research capacity (Reg. Number: CZ.1.05/2.1.00/19.0409). The support by BUT-specific research program (Project No. FEKT-S-17-4595) is gratefully acknowledged. Authors thank Dr. Ondrej Cech for contributing XPS analysis of polysulfide adsorption.

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Microwave reactor record, Powder XRD after TGA analysis in air, time resolved TGA-FTIR 3D spectrum, SEM-EDX spectrum, XPS survey scans, detailed TEM images, Survey XPS scan of MnO/C sample after Li2S6 adsorption test. (DOCX 5572 kb)

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Skoda, D., Kazda, T., Munster, L. et al. Microwave-assisted synthesis of a manganese metal–organic framework and its transformation to porous MnO/carbon nanocomposite utilized as a shuttle suppressing layer in lithium–sulfur batteries. J Mater Sci 54, 14102–14122 (2019). https://doi.org/10.1007/s10853-019-03871-4

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