A sensor element drive circuit is a circuit including a plurality of semiconductor elements formed on a semiconductor substrate for realizing a current control function and a switching function. The current control function is a function of controlling the current flowing between electrodes such that the potential difference between electrodes becomes constant. The switching function is a function for switching between a connected state in which the electrodes are electrically connected to a sensor control apparatus and a cut-off state in which electrical continuity therebetween is broken. When one of an Ip+ terminal, a COM terminal, and a Vs+ terminal is determined to have an anomalous potential, the sensor control apparatus causes the sensor element drive circuit to perform switching from the connected state to the cut-off state, and connects the semiconductor substrate to a negative voltage lower than a ground potential applied to the sensor element drive circuit.

A solid electrolyte includes partially stabilized zirconia in which a stabilizer forms a solid solution in zirconia. The partially stabilized zirconia includes at least monoclinic phase particles and cubic phase particles as crystal particles that configure the partially stabilized zirconia, and an abundance ratio of the monoclinic phase particle is 5 to 25% by volume. The partially stabilized zirconia includes stabilizer low-concentration phase particles of which concentration of the stabilizer at a particle center is equal to or less than 1 mol %, as the crystal particles. The stabilizer low-concentration phase particles have a particle-size distribution of number frequency thereof having a peak at which an average particle size is 0.6 to 1.0 m, and a particle size at 10% of a cumulative number is 0.5 m or greater, and of the overall low-concentration phase particles, 50% by volume or greater belong to the peak.

The invention relates to a solid electrolyte including partially stabilized zirconia, a producing method thereof, and a gas sensor including a solid electrolyte. The partially stabilized zirconia includes crystal particles, the crystal particles include mixed phase particles each having a high-concentration phase and a low-concentration phase, the high-concentration phase being defined such that a concentration of the stabilizer is 4.7 mol % or more, the low-concentration phase being defined as a concentration of the stabilizer is less than 4.7 mol %.

The invention relates to a solid electrolyte comprised of partially stabilized zirconia, and a gas sensor including the solid electrolyte. The partially stabilized zirconia includes crystal particles, the crystal particles include at least stabilizer low-concentration phase particles, and the partially stabilized zirconia further includes voids. Among the stabilizer low-concentration phase particles, the presence rate of the stabilizer low-concentration phase particles where each distance from a void is 5 m or less is 65 volume percent or more. The stabilizer low-concentration phase particles include specific stabilizer low-concentration phase particles each having a distance of 5 m or less from an adjacent void in the voids, a presence rate of the specific stabilizer low-concentration phase particles having 65 volume percent or more.

A solid electrolyte includes partially stabilized zirconia in which a stabilizer forms a solid solution in zirconia. The partially stabilized zirconia includes, as crystal particles that configure the partially stabilized zirconia, stabilizer low-concentration phase particles of which concentration of the stabilizer at a particle center is less than 4.7 mol % and stabilizer high-concentration phase particles of which the concentration of the stabilizer at the particle center is equal to or greater than 4.7 mol %. The partially stabilized zirconia includes an adjacent particle portion in which two or more particles of the stabilizer low-concentration phase particles of which an average particle size is greater than 0.1 m are adjacent. An abundance ratio of the stabilizer high-concentration phase particles on a cross-section of the solid electrolyte is equal to or greater than 70% in terms of area ratio relative to all crystal particles.

A control device performs deterioration diagnosis of a gas sensor including a pump cell and a sensor cell. The control device includes a control unit, a determination value acquisition unit, a diagnosis unit, and a correction unit. The control unit temporarily reduces the oxygen removal capability of the pump cell. The determination value acquisition unit acquires an output ratio of the sensor cell based on an output value of the sensor cell in a state where the oxygen removal capability of the pump cell is temporarily reduced. The diagnosis unit performs deterioration diagnosis of the gas sensor by comparing the output ratio with a determination threshold. The correction unit sets a correction coefficient based on an atmospheric pressure and an oxygen concentration, and also corrects the output ratio using the correction coefficient.

A gas sensor (100) includes a sensor element (120), a metallic shell (110), a powder filler member (133), a first ceramic holder (135) in contact with the rear end of the powder filler member and from which the sensor element protrudes, and a second ceramic holder (131) in contact with the forward end of the powder filler member and from which the sensor element protrudes. The powder filler member has a higher thermal expansion coefficient than that of the first and second ceramic holders. The first ceramic holder, powder filler member, and second ceramic holder are pressed by force application means (118). A relation 0.40<(LM)/L<0.58 holds, where L is the axial distance between the rearward-facing surface of the first ceramic holder and the forward end of the second ceramic holder, and M is the axial length of the powder filler member.

Provided is room temperature stable -phase Bi.sub.2O.sub.3. Ion conductive compositions comprise at least 95 wt % -phase Bi.sub.2O.sub.3, and, at 25 C., the compositions are stable and have a conductivity of at least 10.sup.7 S/cm. Related methods, electrochemical cells, and devices are also disclosed.

The present invention provides solid oxide cells such as fuel cells, electrolyzers, and sensors comprising an electrolyte having an interface between an yttria-stabilized zirconia material and a glass material, in some embodiments. Other embodiments add an interface between a platinum oxide material and the yttria-stabilized zirconia material in the electrolyte. Further embodiments of solid oxide cells have an ion-conducting species such as an ionic liquid or inorganic salt in contact with at least one electrode of the cell. Certain embodiments provide room temperature operation of solid oxide cells.

A gas sensor element includes a solid electrolyte body having oxygen ion conductivity, a measurement electrode provided on one surface of the solid electrolyte body and exposed to a measurement gas, and a reference electrode provided on the other surface of the solid electrolyte body and exposed to a reference gas. Both the measurement electrode and the reference electrode include noble metal particles, solid electrolyte particles having oxygen ion conductivity, and pores. The measurement electrode comprises a surface measurement electrode layer comprising a surface serving as a contact surface with the measurement gas and an intermediate measurement electrode layer disposed in contact with a surface at solid electrolyte body side of the surface measurement electrode layer. The surface measurement electrode layer has a higher porosity than the intermediate measurement electrode layer has. The gas sensor comprises the gas sensor element.