Innovation >> Impact

Nonlinear Electrochemical Impedance Spectroscopy (NLEIS)

Nonlinear Electrochemical Impedance Spectroscopy (NLEIS) is an electrochemical analysis tool which is directly applicable to both solid oxide fuel cells (SOFC) and PEMFCs. NLEIS probes, extracts and quantifies the harmonic response of AC current and voltage measurements. These harmonics provide characteristic information about the chemical and electrical processes that govern fuel cell performance.

Many electrochemical processes are non-linear, such as kinetics, mass transfer and material properties. The existing analysis tools in the marketplace, called “EIS”, only probe the pure-tone portion of current and voltage measurements and cut off the higher-order harmonics. In doing so EIS gives only a linear approximation of non-linear behavior, leading to ambiguous results. NLEIS captures the valuable higher-order harmonics to fully diagnose the impedance of non-linear processes occurring in fuel cells.

NLEIS has been used to successfully distinguish SOFC cathode kinetics and identify SOFC fuel transport limitations.

Licensing Information

Nonlinear Electrochemical Impedance Spectroscopy (NLEIS) is one of the many software programs and tools created at the University of Washington available through our Express Licensing Program. These agreements have standard terms and conditions that allow for rapid licensing by companies, organizations, or individuals.

Academic License

An internal evaluation license is available to academic and nonprofit research institutions at no charge in exchange for feedback.


Commercial License

Download the commercial fee-based NLEIS Site License.


The conditions and financial terms of this license apply only to those who download the license, sign it and return it "as is" to UW CoMotion. Some Express Licenses may be modified for an additional cost. Other licensing arrangements may be available.

For Descriptive and Technical Information

Stuart Adler
355 Benson Hall
Box 351750
Seattle, WA 98195-1750


For Licensing Information/Customer Service

Express Licensing Program
UW CoMotion
4545 Roosevelt Way NE, Suite 400
Phone: (206) 543-3970
Fax: (206) 616-3322