This study investigates the mixing characteristics of non-Newtonian liquids flowing through a microfluidic channel equipped with a two-part cylinder, which possesses spatially varying zeta potentials and is subjected to a time-periodic electric field. A finite-element-based numerical framework is employed to solve the transport equations, governing the underlying mixing dynamics, using physically justified boundary conditions. The influence of amplification factor of the electric field amplitude, the angular velocity of the time-periodic forcing, the Carreau number, and the flow behaviour index, on the flow field, shear stress distribution, and mixing performance is systematically investigated. Results show that, at maximum potential of the applied field, the core flow velocity, magnitude of reverse flow velocity, and shear stress increase with increasing amplification factor, while these quantities decline at minimum potential. Consequently, temporal mixing efficiency exhibits a non-monotonic response due to competing effects of convective enhancement and attenuation. Despite this, both the maximum and average mixing efficiencies improve substantially at higher amplification factors relative to steady electric field operation. Increasing the angular velocity of the time-periodic field similarly enhances the effectiveness of mixing. It is shown that the flow behaviour index exerts minimal influence at low Carreau numbers due to negligible changes in apparent viscosity. In contrast, at higher Carreau numbers, reduced viscosity intensifies vortex formation, thereby increasing mixing efficiency, particularly for lower flow behaviour indices. The inclusion of Poincaré section, energy consumption ratio, and mixing performance improves the current analysis. Overall, the findings demonstrate that time-periodic electric fields can significantly augment mixing of non-Newtonian liquids, and seem to provide insights into the design of efficient micromixers, typically used for diagnostic applications.