Sensor element for determining gas components in gas mixtures and method for manufacturing the same

A method for manufacturing a sensor element for determining an oxygen concentration in an exhaust-gas mixture of an internal combustion engine, the method comprising:

• providing at least one pump cell which includes a first electrode and a second electrode, the first electrode being situated in a measuring gas space of the sensor element, wherein the pump cell is configured to pump oxygen one of into and out of the measuring gas space of the sensor element, and wherein a surface area of the second electrode exposed to the exhaust-gas mixture is selected to be greater than a surface area of the first electrode exposed to the exhaust-gas mixture;
• and
• providing a diffusion barrier for the second electrode, wherein the diffusion barrier acts against the exhaust-gas mixture diffusing to the second electrode, a diffusion resistance of the diffusion barrier being determined by at least one of porosity and layer thickness of the diffusion barrier, and wherein the diffusion resistance of the diffusion barrier is selected such that, for a predefined pump voltage applied to the first electrode and the second electrode, a resulting pump current flowing between the first electrode and the second electrode is substantially the same as a hypothetical pump current flowing between the first electrode and the second electrode in the case where the diffusion barrier for the second electrode is not provided and the first electrode and the second electrode have the same surface areas exposed to the exhaust-gas mixture.