Computational study of the structure of ternary ionic liquid/salt/polymer electrolytes based on protic ionic liquids

Abstract The stability of binary mixtures of several protic ionic liquids (ethylammonium nitrate, ethylammonium acetate and ethylammonium tetrafluoroborate) with polyethylene oxide is studied by means of molecular dynamics simulations. The solubility range is seen to be wider for ethylammonium acetate, and the structure and single-particle dynamics of its ternary mixtures with lithium acetate are then studied. The structure of liquid mixtures of lithium acetate with the ionic liquid is seen to be seldom modified by the addition of the polymer, with very limited hydrogen bonding between the ionic liquid and the polymer taking place. Moreover, lithium is seen to be solvated in the liquid phase forming [Li(ACE)4]−3 tetrahedral complexes irrespective of the presence of the polymer, with very limited binding of metal cations to oxygen atoms in the polymer backbone. Hence, the registered single particle dynamics and lithium transport takes place in practically the same way as in the liquid phase with almost no interference of the polymer, contrarily to previously reported results for other ionic liquids.