The ionic behavior of an aromatic lithium sulfonyl imide, i.e. lithium bis(4nitrophenyl)sulfonylimide, has been investigated in an amorphous poly(oxyethylene) network and compared to that of usual lithium salts dissolved in the same host polymer. The NO2 groups which are substituents at both phenyl groups, are expected to induce a strong electron-withdrawing effect on the imide negative charge to provide large delocalization and therefore generate high charge carrier concentration. The conductivities observed are lower than those of lithium salts such as (CF3SO2)(2)NLi (LiTFSI) dissolved in the same host polymer. An important increase of T-g with salt concentration reflects a greater stiffness of the polymer induced by the aromatic rings, which reduces mobility, and might account for the lower conductivity. Interestingly, the aromatic imide exhibits higher cationic mobility with t(+) ranging between 0.4 and 0.45, compared to 0.08-0.12 for the fluorinated imide. Cyclic voltammetry shows that lithium bis(4-nitrophenyl)sulfonylimide undergoes irreversible reduction before lithium plating, which has been attributed to the presence of nitro group. (C) 2000 Elsevier Science Ltd. All rights reserved.