Halogen-free ionic liquid as an additive in zinc(II)-selective electrode: Surface analyses as correlated to the membrane activity

► A halogen-free ionic liquid, as an additive for Zn(II) electrode, increased the selectivity of the sensor. ► X-ray photoelectron- and ion scattering spectroscopy proved ion transport through the membrane. ► Atomic force microscopy explored the morphological changes of the membrane surface when conditioned.