Salt-doped poly(ethylene oxide)-based block copolymers have been considered to be promising candidates for polymer electrolytes which require strong mechanical property as well as high ionic conductivity. We studied the phase behavior of poly(styrene-b-ethylene oxide) block copolymers doped with various salts over a range of EO:ion ratios. Small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM), and differential scanning calorimetry (DSC) experiments were used to characterize the phase behavior of our neat and salt-doped copolymers. Samples were prepared in an argon atmosphere and rigorously dried to reduce the effects of moisture uptake on phase behavior. We found that the copolymer microstructure can be tuned by variations in the salt and counterion, as well as the salt doping ratio. Additionally, we observed thermal order-order transitions that were caused by the crystallization of confined PEO-lithium complexes.