SOLID-STATE ELECTROCHEMICAL CO_2 SENSOR BY COUPLING LITHIUM ION CONDUCTOR (Li_2CO_3-Li_2PO_4-Al_2O_3) WITH OXIDE ION-ELECTRON MIXED CONDUCTOR (La_(0.9)Sr_(0.1)MnO_3)

摘要

A solid-state electrochemical cell for sensing CO_2 was constructed by incorporating a lithium ion conductor (Li_2CO_3-5mol% Li_3PO_4-6mol%Al_2O_3) with an oxide ion-electron mixed conductor (La_(0.9)Sr_(0.1)MnO_3). The electromotive force (EMF) of the cell depended logarithmically on the CO_2 partial pressure in CO_2/O_2 gas mixtures at temperatures between 300 and 400 ℃, and became a steady state value within 1 min at 400 ℃. The CO_2 sensitivity of this cell was hardly affected in coexistence of O_2 and H_2O. However, long term stability of the cell should still be improved. The CO_2 sensing mechanism of the cell was discussed.