Hi everyone,

I'm conducting Zn²⁺ transference number measurements using symmetric Zn || separator || Zn coin cells without any surface treatment. The procedure follows the Bruce–Vincent–Evans method: I first measure the initial EIS at open-circuit voltage (OCV), then apply a 10 mV DC bias until steady-state current is reached, and finally perform a second EIS measurement.

However, I consistently observe that the resistance after polarization (R_ss) is lower than the initial resistance (R₀), even though the system appears to reach a steady current. This behavior is reproducible across multiple cells.

• Is a rest period required after polarization before performing EIS?
• Could this behavior be an artifact related to coin cell geometry or Zn surface conditions?

Any insight or shared experience would be greatly appreciated. Thank you in advance!

Any insights or suggestions would be greatly appreciated. Thanks in advance!