EIS of a Pt disc electrode (blue) and an IS-1 SPE (red curve) with a carbon ink working electrode in K3[Fe(CN)6] + K4[Fe(CN)6] solution; Insert- Zoom in on blue curve

EIS of a Pt disc electrode (blue) and an IS-1 SPE (red curve) with a carbon ink working electrode in K3[Fe(CN)6] + K4[Fe(CN)6] solution; Insert- Zoom in on blue curve