Flame-retardant properties of in situ sol-gel synthesized inorganic borosilicate/silicate polymer scaffold matrix comprising ionic liquid

Abstract

This paper focuses on the superiority of organic-inorganic hybrid ion-gel electrolytes for lithium-ion batteries (LiBs) over commercial electrolytes, such as 1 M LiPF₆ in 1:1 ethylene carbonate (EC): dimethyl carbonate (DMC) {1 M LiPF₆-EC: DMC}, in terms of their flame susceptibility. These ion-gel electrolytes possess ionic liquid monomers, which are confined within the borosilicate or silicate matrices that are ideal for non-flammability. Naked flame tests confirm that the organic-inorganic hybrid electrolytes are less susceptible to flames, and these electrolytes do not suffer from a major loss in terms of weight. In addition, the hybrids are self-extinguishable. Therefore, these hybrids are only oxidized when subjected to a flame unlike other commercial electrolytes used in lithium-ion batteries. Supplementary analyses using differential scanning calorimetric studies reveal that the hybrids are glassy until the temperature reaches more than 100°C. The current results are consistent with previously published data on the organic-inorganic hybrids.

Keywords

inorganic polymeric borosilicate network / organic-inorganic hybrids / self-extinguishability / nonflammability / lithium batteries / flame-retardants

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Acknowledgments

This work was supported by the MEXT scholarship of the Japanese Government. The authors wish to thank Prof. Vito Di Noto of the University of Padova, Italy for helping with the DSC measurements.

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