Solid electrolyte CO2 sensor with lithium-ion conductor and Li transition metal complex oxide as solid reference electrode

Solid-state CO2 sensors comprising O-2, LiFeO2-LiFe5O8/Li+ conducting glass ceramics/Li2CO3-Li3PO4/Au,CO2, O-2 have been developed, where Li2CO3 acts as a lithium-ion conductor and a sensing electrode material, with the two-p hase mixture LiFeO2-LiFe5O8 as the reference electrode. The electromotive f orce (emf) of the sensor responded well to changes of CO, concentration at temperatures around 500 degreesC, while it is independent of the oxygen par tial pressure. Its long-term stability is good. the emf of the sensor was r eproducible within +/-3 mV over than I year in an environment of 95% humidi ty, This result shows that the developed CO2 sensors have high humidity res istance and good stability. The sensing mechanism is also discussed, (C) 20 01 The Electrochemical Society. [DOI: 10.1149/1.1379743] All rights reserve d.