Surface functionalized silica nanofiber cross-linked guar gum as novel nanocomposite polymer gel electrolytes towards green energy storage solutions

This work focuses on synthesizing and assessing guar gum (GG)-based cross-linked nanocomposite polymer gel electrolytes (NPGEs) as an innovative separator for environmentally friendly energy storage purposes. The synthesis procedure involves cross-linking Octadecyltrichlorosilane (OTS) functionalized SiO₂ nanofibers (f-SiO₂) with GG, followed by uptake of liquid electrolytes. Maximum ionic conductivity of 6.7 × 10^-3 Scm⁻¹ is achieved at 5 wt% f-SiO₂. XRD and XPS investigations show that nanofibers create conducting channels in NPGEs, improving ionic conductivity. The cross-linked NPGEs exhibit an outstanding electrochemical potential window of 4.8 V, enhanced lithium ion transference number (t₊) of 0.58, and enhanced compatibility at the interface with metal electrodes. The initial discharge capacity at 0.5C was measured to be 134 mAh g⁻¹ for Li|NPGE|LiFePO₄ cell in the first cycle and 125 mAh g⁻¹ after 50 cycles. The synthesized cross-linked NPGEs also show enhanced thermal and mechanical properties, as investigated by TGA and UTM analyses.

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