Changes in lithium ion coordination in polymer gel electrolyte materials have been studied by Fourier transform infrared (FTIR) spectroscopy as a function of composition. Two plasticizers, propylene carbonate and dimethyl sulfoxide, and two polymers, polyvinylidene fluoride-co-hexafluoropropylene (Kynar flex), and poly(ethylene glycol 400)dimethacrylate (PEG400DMA), have been compared, and their coordination to the cation has been determined. The salt used in all samples is lithium bis(trifluoromethane sulfone)imide, Li(TSFI). In order to determine the changes of lithium coordination from the resulting FTIR spectra, a quantitative band-shape analysis of these spectra has been performed.