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Solid oxide cell long-term durability experiments are resource-intensive and have limited ability to capture the interdependence of microstructural evolution and electrochemical performance. Studies of microstructural degradation mechanisms are usually limited to before and after life-test images. Here we describe a life testing method that simultaneously operates multiple symmetric cells under different conditions, simultaneously providing information on electrolysis and fuel cell operation, while sampling the microstructure during operation. The method utilizes laser-cutting to exactly define different cell areas, allowing testing under different current densities with a single current source, and facilitating removal of segments of the cellsduringlife tests, allowing for microstructural evaluation at intermediate times. The method is demonstrated in Ni-YSZ / YSZ / Ni-YSZ fuel-electrode-supported cells at low H2O/H2ratios. Characterization using SEM-based imaging techniques shows pronounced microstructural damage that increases rapidly with increasing current density and time, mirroring observed electrochemical degradation. The present results agree with prior reports for SOC operation under such conditions but reveal new features of the degradation process via the unique capability of time-resolved imaging.
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The Poor Academic’s DC-Offset for Reversing Polarity in Electrochemical Cells: Application to Redox Flow Cells
We provide a simple and inexpensive manual DC-offset method for extending the accepted voltage range of a battery cycler to negative voltages, without interfering with the actual operation of the electrochemical cell under the test or exceeding the voltage specs of the battery cycler instrument. We describe the working principles of the method and validate the proposed setup by operating short-term and long-term redox flow battery cycling using compositionally symmetric cell, with open-circuit voltage of zero, and full cell configurations. The method can be used to extend the capability of battery cycler instrumentation to operate any electrochemical cell that requires the polarity to be reversed during operation. Applications include cycling of other symmetric cells (e.g., Li-ion cells), implementation of polarity reversal steps for rejuvenation of electroactive species or rebalancing electrochemical cells, and alternating polarity for electrochemical synthesis.
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- Award ID(s):
- 1914543
- PAR ID:
- 10371833
- Publisher / Repository:
- The Electrochemical Society
- Date Published:
- Journal Name:
- Journal of The Electrochemical Society
- Volume:
- 169
- Issue:
- 9
- ISSN:
- 0013-4651
- Page Range / eLocation ID:
- Article No. 090527
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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