For poly(ethylene oxide) (PEO) melts containing lithium perchlorate (LiClO4), angular frequency omega dependence of the dynamic dielectric properties under steady shear flow was measured using a rheodielectric instrument. The instrument also enabled measurements of the dielectric properties in the quiescent state as well as the linear and nonlinear rheological properties. A significant increase in the zero-shear viscosity eta(0) was observed upon addition of LiClO4 to PEO, and this increase was attributed to Li+-mediated intermolecular bridging of the PEO chains formed in the quiescent state. Significant shear thinning of the steady-state viscosity eta(gamma) was observed with increasing shear rate gamma, suggesting the flow-induced breakup of these bridges. The presence of liberated ions was detected directly by dielectric experiments under steady shear flow. The dielectric dispersion (due to the electrode polarization of the ions) shifted to higher omega with increasing gamma, indicating an increase in the ionic conductivity sigma. The dispersion curves for different values collapsed onto a single master curve when plotted against a reduced frequency, {lambda(gamma)}(-1)omega where lambda(gamma) was a gamma-dependent shift factor representing the increase of sigma. This result strongly suggested that the increase of sigma under shear flow was due to an increase in the ionic mobility mu by the factor of lambda(gamma) and not due to a change in the number density of ions. Furthermore, excellent agreement was found between the eta(gamma)/eta(0) ratio and {lambda(gamma)}(-1). This agreement reflected a strong motional cooperativivity between the PEO chain segment and ion (Li+).