In addition to confirming electrolyte exchange, the Raman spectra in Figure provide insights into the LHCE solvent structure and electrolyte-polymer interactions. These topics are discussed in detail in the SI (Figure , Table , and Figure ). Briefly, the high extent of Li + FSI -coordination (~99-100%) in the pure LHCE and gel-2 confirms that the HCE property of the LHCE is intact in each case. Shifts in the type of Li + FSI -ion pairs, on the other hand, suggest the possibility of electrolyte-polymer interactions. past that of PYR14 + (~800-1100 cm -1 ) to sharpen relevant peaks (dashed line = main PYR14 + peak in that region).