Ferroelectric Dispersed Composite Solid Electrolyte for CO2 Gas Sensor

The Li₂CO₃:LiNbO₃ composite system was investigated for the application in electrochemical gas sensor. The conductivity maximum is observed for 50Li₂CO₃+50LiNbO₃. An enhancement in conductivity is understood to be due to the percolation threshold. The composite is also seen less sensitive to moisture. Potentiometric sensors are obtained using optimized composition. At the reference electrode, the activity of Li⁺ is fixed by using open reference electrode material. Good reversibility of cell emf was observed for P<INF>CO₂</INF> ranging from 200 ppm to 20% at 400°C. The cell response was Nernstian, following nearly two-electron reaction. The sensor showed negligible cross-sensitivity to moisture. Developed solid electrolyte not only exhibit shorter response time but also improves over all performance relative to the sensor based on pure carbonate.