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Abstract Solid polymer electrolytes for lithium batteries promise improvements in safety and energy density if their conductivity can be increased. Nanostructured block‐copolymer electrolytes specifically have the potential to provide both good ionic conductivity and good mechanical properties. This study shows that the previously neglected nanoscale composition of the polymer electrolyte close to the electrode surface has an important effect on impedance measurements, despite its negligible extent compared to the bulk electrolyte. Using standard stainless steel blocking electrodes, the impedance of lithium salt‐doped poly(isoprene‐b‐styrene‐b‐ethylene oxide) (ISO) exhibits a marked decrease upon thermal processing of the electrolyte. In contrast, covering the electrode surface with a low molecular weight poly(ethylene oxide) (PEO) brush results in higher and more reproducible conductivity values, which are insensitive to the thermal history of the device. A qualitative model of this effect is based on the hypothesis that ISO surface reconstruction at the different electrode surfaces leads to a change in the electrostatic double layer, affecting electrochemical impedance spectroscopy measurements. As a main result, PEO‐brush modification of electrode surfaces is beneficial for the robust electrolyte performance of PEO‐containing block‐copolymers and may be crucial for their accurate characterization and use in Li‐ion batteries.
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This content will become publicly available on February 1, 2026
Probing Ion-Blocking Electrode Rigs for Ionic Conductivity in Hybrid Solid Polymer Electrolytes
Solid electrolytes are critical for structural batteries, combining energy storage with structural strength for applications like electric vehicles and aerospace. However, achieving high ionic conductivity remains challenging, compounded by a lack of standardized testing methodologies. This study examines the impact of experimental setups and data interpretation methods on the measured ionic conductivities of solid polymer electrolytes (SPEs). SPEs were prepared using a polymer-induced phase separation process, resulting in a bi-continuous microstructure for improved ionic transport. Eight experimental rigs were evaluated, including two- and four-electrode setups with materials like stainless steel, copper, and aluminum. Ionic conductivity was assessed using electrochemical impedance spectroscopy, with analysis methods comparing cross-sectional and surface-area-based approaches. Results showed that the four-electrode stainless steel setup yielded the highest ionic conductivity using the cross-sectional method. However, surface-area-based methods provided more consistent results across rigs. Copper setups produced lower conductivities but exhibited less data variability, indicating their potential for reproducible measurements. These findings highlight the critical influence of experimental design on conductivity measurements and emphasize the need for standardized testing protocols. Advancing reliable characterization methods will support the development of high-performance solid electrolytes for multifunctional energy storage applications.
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- Award ID(s):
- 2050956
- PAR ID:
- 10658054
- Publisher / Repository:
- IOPScience
- Date Published:
- Journal Name:
- Journal of The Electrochemical Society
- Volume:
- 172
- Issue:
- 2
- ISSN:
- 0013-4651
- Page Range / eLocation ID:
- 020523
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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