Library · Materials, chemistry & fabrication
What Electrochemical Impedance Spectroscopy (EIS) got wrong, from 18 theses
Summary written by a model from the records below: The records describe methodological limitations and experimental failures encountered when applying electrochemical impedance spectroscopy across diverse electrochemical systems. Common challenges include equivalent circuit modeling errors, parasitic electrode crosstalk, geometry and spacing defects, incompatible electrolytes, and high-frequency instrumental artifacts. These records come from graduate theses, 2021 to 2026, each labeled with its degree where the repository states it, and each links to its thesis. They were extracted by language models reading the full text, so treat each as a lead to read, not a verdict.
Plus 10 problems the authors left open, listed at the end.
Failure modes, by theses reporting them
Select a mode to jump to its records.
Suboptimal electrolyte conductivity and liquid environments obscuring spectral features
Extreme solution conductivity levels, whether excessively high ionic strength causing electrical saturation or low conductivity causing huge charge transfer resistances, masked target impedance responses. Furthermore, low-frequency noise, liquid immersion artifacts, and internal open-circuit electric fields prevented the observation of semicircles and depletion layers.
Tried and failed
electrochemical impedance spectroscopy for corrosion rate measurement applied to steel alloys in amino acid solvents. Outcome: no signal. Reason: low-frequency noise and lack of semicircular response prevented polarization resistance fitting
Capture of CO₂ Using Potassium Salts of Amino Acids and Guanidine-Based Ligands · Georgia Tech · PhD
Tried and failed
impedance biosensing with interdigitated electrodes applied to biomolecule detection in ionic buffer. Outcome: no signal. Reason: ionic buffer conductivity caused electrical saturation, masking impedance changes from binding
Capillary-driven Microfluidic Biosensing Platforms for Digital Biomolecule Detection · Texas Tech · PhD
Considered and rejected
Considered and rejected: Rejected using asymmetric pH electrolytes for EIS depletion region characterization because intrinsic open-circuit electric fields obscure early depletion layer formation.
Ion Management And Mass Transport For (photo-) Electrochemical Conversions · Penn · PhD
Tried and failed
Electrochemical impedance spectroscopy in liquid aqueous environment applied to ultra-thin freestanding ceramic membranes. Reason: Liquid immersion produced severe measurement artifacts, requiring testing in humidified gas instead
Overparameterization and non-uniqueness in equivalent circuit modeling
Adding excessive circuit elements or multiple constant phase elements caused overfitting, large parameter fitting uncertainties, and obscured physical interpretations. Fitting was also rejected because equivalent circuit models are often mathematically non-unique and lack scientific meaning.
Tried and failed
two constant phase element equivalent circuit modeling applied to impedance spectroscopy of functionalized semiconductor interfaces. Outcome: overfit. Reason: overparameterization caused overfitting and obscured the physical interpretation of chemical capacitance
Electronic structure and photoelectrochemistry of Si(111) functionalized by acene derivatives · UT Austin · PhD
Tried and failed
adding circuit elements to equivalent circuit model applied to electrochemical impedance spectroscopy fitting. Outcome: overfit. Reason: increased discrepancies and parameter fitting uncertainties due to model overparameterization
Integrated characterization and design of cathode microstructure for high performance solid oxide fuel cells · Imperial · PhD
Considered and rejected
Considered and rejected: Rejected impedance spectroscopy equivalent circuit curve fitting because the circuit models are typically non-unique and parameters are not scientifically meaningful.
Electric Polarization in Electronic Conductors · University at Buffalo · PhD
Inadequacy of simplified or ideal circuit elements for complex interfaces
Simple resistive models, ideal double-layer capacitors, and standard Randles circuits failed to capture non-ideal interfacial phenomena such as cellular infiltration, surface roughness, and porous layer diffusion. Researchers rejected these basic elements in favor of constant phase elements, Warburg impedances, or more complex equivalent circuits.
Considered and rejected
Considered and rejected: Purely resistive Marker 1 impedance evaluation was rejected for in vivo FBR monitoring due to high low-frequency capacitance from cellular infiltration, requiring an equivalent circuit model.
Considered and rejected
Considered and rejected: Rejected the Randles equivalent circuit (Circuit 1) and active corrosion model (Circuit 2) for EIS fitting of Cu in [C4C1im]Cl, adopting Circuit 4 (porous layer with Warburg impedance) instead
An investigation into Ionic Liquids, their physicochemcial properties, and corrosion of industrially relevant metals · Imperial · Doctorate
Considered and rejected
Considered and rejected: Rejected modeling composite cathode local impedance using an ideal double-layer capacitor in favor of a constant phase element (CPE) to account for surface roughness.
Charakterisierung des Festelektrolytsystems (1−x) Li3PS4 + x LiI sowie dessen Anwendung in Lithiumionen-Festkörperbatterien Characterization of the solid electrolyte system (1-x) Li3PS4 + x LiI and its application in lithium ion all-solid-state batteries · University of Marburg · PhD
Reference and counter electrode artifacts confounding working electrode impedance
Conventional reference electrodes and reactive counter electrodes proved unreliable for isolating individual electrode contributions. SEI growth, solvent degradation, and inter-electrode crosstalk at counter electrodes confounded measurements of the positive electrode or cathode.
Considered and rejected
Considered and rejected: Rejected analyzing fluorinated electrolytes (HFEs) using LTO full cells in GEIS due to severe SEI growth from FEC on the LTO anode confounding cathode impedance measurements.
Deliniating interfacial and bulk phenomena influencing reversibility of high-voltage phase transitions in layered-oxide cathodes · UT Austin · PhD
Considered and rejected
Considered and rejected: Rejected using metallic Li counter electrodes for long-term isolated evaluation of positive electrode materials due to severe solvent degradation and crosstalk inducing CEI impedance growth.
Understanding degradation in lithium-ion and lithium-air batteries · Nottingham · PhD
Cell geometry and electrode spacing distorting impedance spectra
Cell layout flaws, including excessive electrode overhang, overly large electrode separation, and narrow microgaps, severely distorted impedance measurements. These geometric issues caused erratic or unrepeatable spectra, microfabrication shorting defects, and the obscuring of low-frequency diffusion arcs.
Tried and failed
electrochemical impedance spectroscopy applied to single-layer pouch cells. Outcome: unstable. Reason: extreme electrode overhang and long diffusion pathways caused erratic, non-repeatable spectra
The effect of micro and nano scale phenomena on system level design and engineering of hybrid pemfc systems · Imperial · PhD
Tried and failed
Non-faradaic impedance spectroscopy on microgap interdigitated electrodes applied to bacterial cell detection. Outcome: unstable. Reason: High microfabrication shorting defects and unrepeatable impedance spectra at small interelectrode spacings
The impact of mass transport and surface charging on the performance of field effect transistor biosensors · Georgia Tech · PhD
Considered and rejected
Considered and rejected: Rejected using a 1 mm thick EPDM sealing ring for transference number measurements despite good margin sealing, because it enforces an electrode distance >0.5 mm which obscures the low-frequency electrolyte diffusion arc.
Redox probe electrostatic repulsion and microelectrode burnout
Electrostatic repulsion between similarly charged redox probes and surface biomolecules prevented the measurement of charge transfer resistance in Faradaic impedance. Additionally, conventional redox probe concentrations caused electrical burnout and physical degradation of thin-film microelectrodes.
Tried and failed
Faradaic electrochemical impedance spectroscopy with like-charged probe applied to biosensor surface functionalization monitoring. Outcome: no signal. Reason: Electrostatic repulsion between negatively charged redox probe and negatively charged biomolecules prevented charge transfer resistance changes
Methods to Improve the Stability and Selectivity of Electronic Biosensors · Georgia Tech · PhD
High-frequency cable artifacts and inter-electrode crosstalk
High-frequency parasitics, such as cable-induced pseudo-inductive loops, produced non-physical negative resistances in equivalent circuit fits. In multi-electrode setups, inter-electrode crosstalk at high frequencies severely distorted dielectric impedance measurements.
Tried and failed
simple standard RC equivalent circuit model fitting applied to electrochemical impedance spectroscopy data. Reason: high-frequency pseudo-inductive cable artefacts produced non-physical negative resistance values
Organic electrochemical transistors with PVA hydrogels/PEDOT:PSS channel · Imperial · Master's
Tried and failed
multi-electrode dielectric impedance spectroscopy applied to in-line fluid flow monitoring. Reason: inter-electrode cross-talk at specific high frequencies severely distorted impedance measurements
REAL-TIME MONITORING OF CELL AND BIOINK PROPERTIES USING DIELECTRIC IMPEDANCE SPECTROSCOPY FOR EXTRUSION BIOPRINTING · Cornell · PhD
Left open by the authors
Problems the authors named and did not get to.
Left open
Investigate the impact of battery State-of-Health degradation and SEI growth on impedance phase-based temperature estimation. Blocker: Requires conducting physical battery cycling and degradation experiments with electrochemical impedance spectroscopy instrumentation
Abuse detection in Li-ion batteries using Electrochemical Impedance Spectroscopy · EPFL · PhD
Left open
Isolate the individual influences of ionic conductivity, redox mediator kinetics, Li2O2 reaction kinetics, and mass transport on charge overpotential. Blocker: Requires a wet chemistry and electrochemistry laboratory to synthesize electrolytes and measure kinetics and overpotentials in battery cells.
Towards comprehensive design of electrolytes for electrochemical energy storage · MIT · PhD
Left open
Investigate dissolved transition metal effects, like Fe species, on SEI growth and impedance in lithium-ion batteries using operando spectroscopy. Blocker: Requires a physical electrochemical laboratory with operando soft X-ray spectroscopy apparatus and battery assembly equipment
Mapping chemical, ionic and electronic properties of high capacity cathode materials for lithium-ion batteries · Oxford · PhD
Left open
Investigate timescales and resistances of charge transfer, desolvation, and SEI polarization across different salt anions in battery electrolytes. Blocker: Requires wet lab electrochemical testing, electrolyte preparation, and impedance spectroscopy equipment.
Structural engineering of lithium-ion battery electrodes for the production of stable, energy-dense storage · UT Austin · PhD
Left open
Apply electrochemical impedance spectroscopy (EIS) to estimate health and predict remaining useful life at the battery module or pack level. Blocker: Requires a physical battery module/pack setup and EIS hardware to collect experimental pack-level impedance data.
Lithium-Ion Battery State of Health Estimation and Remaining Useful Life Prediction: Practical Techniques for Varied Operating Conditions · University of Windsor · Master's
Left open
Optimize electrochemical generation of superoxide radical stock solutions using varied electrode materials, O2-saturated electrolytes, and higher reaction voltages. Blocker: Requires an electrochemistry wet lab, electrode materials, chemical reagents, and physical measurement apparatus.
Novel (Advanced) Oxidation and Disinfection Processes based on Reactions of Free Available Chlorine or Hydrogen Peroxide with Unconventional Activating Agents: Superoxide Radical a · University of Washington · PhD
Left open
Investigate heterogeneous electrochemical and chemo-mechanical degradation at cathode-electrolyte interfaces using in-operando X-ray fluorescence microscopy combined with X-ray absorption spectroscopy. Blocker: Requires synchrotron beamline facilities, specialized in-operando XFM/XAS instrumentation, and physical thin-film solid-state battery samples.
Left open
Model pulse charging and current harmonics using EIS battery models and develop an EIS-based charging protocol optimization methodology. Blocker: Requires battery testing apparatus and electrochemical impedance spectroscopy (EIS) hardware to evaluate pulse charging effects.
Lithium-Ion Battery State of Health Estimation and Remaining Useful Life Prediction: Practical Techniques for Varied Operating Conditions · University of Windsor · Master's
Left open
Elucidate the elementary reaction steps determining how electrolytes influence sulfur redox near the end of discharge in Li-SF6 batteries. Blocker: Requires wet-lab electrochemical testing and specialized battery diagnostic apparatus.
Tailoring Fluoride/Fluorine Bond Activity for High-Energy Li and Li-ion Batteries · MIT · PhD
Left open
Elucidate specific ion-ion interactions determining the open-circuit voltage inflection point beyond ~0.4 M KCl in mixed-electrolyte bipolar membranes. Blocker: Requires experimental wet-lab electrochemical testing and mixed-electrolyte bipolar membrane characterization apparatus.
Membrane-Electrolyte System Studies for Aqueous Redox Flow Reactors · Harvard · PhD
Who has worked on this
Authors of the public theses cited on this page, most-cited first.
- Ahnaf Akif Rahman · University of Windsor · Master's · 2025
Lithium-Ion Battery State of Health Estimation and Remaining Useful Life Prediction: Practical Techniques for Varied Operating Conditions - Alicia Matavosian · Cornell · PhD · 2025
REAL-TIME MONITORING OF CELL AND BIOINK PROPERTIES USING DIELECTRIC IMPEDANCE SPECTROSCOPY FOR EXTRUSION BIOPRINTING - Thomas Young George · Harvard · PhD · 2025
Membrane-Electrolyte System Studies for Aqueous Redox Flow Reactors - Andrea Gabriele Jaegermann · University of Marburg · PhD · 2025
Characterization of Lithium Transport in Lithium Titanate Thin Films & their Utilization for Transference Number Measurements of Electrolytes for Lithium-Ion Batteries Charakterisierung des Lithiu - Shubham Sharad Bhoir · EPFL · PhD · 2025
Abuse detection in Li-ion batteries using Electrochemical Impedance Spectroscopy - Hilena Gezahagne · Georgia Tech · PhD · 2024
Methods to Improve the Stability and Selectivity of Electronic Biosensors - Oisin Shaw · Imperial · PhD · 2024
The effect of micro and nano scale phenomena on system level design and engineering of hybrid pemfc systems - Abishek Kasturi · Georgia Tech · PhD · 2024
Capture of CO₂ Using Potassium Salts of Amino Acids and Guanidine-Based Ligands - Zheng Xie · Imperial · PhD · 2024
Integrated characterization and design of cathode microstructure for high performance solid oxide fuel cells - MW Fraser · Oxford · PhD · 2024
Mapping chemical, ionic and electronic properties of high capacity cathode materials for lithium-ion batteries - Julia Brug · Imperial · Master's · 2023
Organic electrochemical transistors with PVA hydrogels/PEDOT:PSS channel - Keegan Leigh Mendez · MIT · PhD · 2023
Multifunctional soft robotic devices and cardiac benchtop models for improved therapy delivery and development
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