Completely\nMiscible Polymer Blend Electrolyte Studied\nby Small-Angle Neutron Scattering

We\nstudied blend electrolytes comprising poly(ethylene oxide) (PEO),\npoly(pentyl malonate) (PPM), and lithium bis(trifluoromethanesulfonyl)imide\n(LiTFSI). Ion transport in the blend electrolytes resembles transport\nin PEO/LiTFSI and PPM/LiTFSI systems. The thermodynamic properties\nof the PEO/PPM/LiTFSI blend electrolytes were studied by small-angle\nneutron scattering (SANS). The effect of added salt on polymer blend\nthermodynamics is quantified by an effective Flory–Huggins\ninteraction parameter, χ<sub>eff</sub>. The blend electrolytes\nexhibit one-phase, and χ<sub>eff</sub> is negative at all salt\nconcentrations. This is noteworthy because the addition of salt generally\nleads to macrophase-separation in polymer blends.