Steady-state Systems

Measuring an EIS spectrum takes time (often many hours). The system being measured must be at a steady state throughout the time required to measure the EIS spectrum. A common cause of problems in EIS measurements and their analysis is drift in the system being measured.

In practice a steady state can be difficult to achieve. The cell can change through adsorption of solution impurities, growth of an oxide layer, build-up of reaction products in solution, coating degradation, temperature changes, and more.

Standard EIS analysis tools may give you wildly inaccurate results on a system that is not at a steady state.