Publications

Characterization of electrochemical surface area and porosity of zirconia sensors

Tsui, Lok K.; Benavidez, Angelica; Evans, Lindsey E.; Garzon, Fernando

Solid-state zirconia sensors are used in a wide variety of applications including controlling the air to fuel ratio in combustion engines and pollution monitoring. These sensors use either a layer of zirconia as a solid-state ionic electrolyte or a gasporous ceramic as a protective layer. There is a need for quantitative methods to assess the tortuosity of these porous layers and the size of the electrode area exposed which can be performed on completed sensor devices. We demonstrate using electrochemical double layer capacitance and transport studies in aqueous potassium ferri/ferro-cyanide electrolytes that these parameters can be readily measured. The technique is demonstrated on sensors procured from ESL ElectroScience as well as sensors produced in-house using additive manufacturing. The processes that we develop can be applied as quality control to ensure sample-to-sample reproducibility of the porous layer.