It is shown that the addition of calix[6]pyrrole to polyether based electrolytes doped with LiBF4 results in an considerable increase in the cation transport number t L i + as confirmed by dc–ac current techniques as well as by PFG NMR studies. The value of t L i + in composite electrolytes beyond a certain minimum value weakly depends on the concentration of added calix[6]pyrrole. The increase in lithium transference number is associated with a decrease in ionic conductivity of composite polymeric electrolytes compared to the pure PEO–LiBF4 systems.