Solid State Ionics, Vol.86-88, 107-111, 1996
The Effect of Ion Substitution in Sodium-Conducting Solid Electrolytes on the Reversibility of the Electrode-Solid Electrolyte Interface
The reversibility of the sodium-cobalt bronze NaxCoO2 interface with a solid sodium-conducting NASICON-type electrolyte is studied by means of the electrochemical impedance method. Also studied were electrolytes of two compositions, a stoichiometric one, Na3Zr2Si2PO12 (I) and that doped with cobalt oxide, Na3.06Zr1.94Co0.06Si2PO12 (II). The experimental temperature was 22+/-1 degrees C. The exchange current of the electrode reaction, Na-e(-) = Na+ was found to increase by almost a decade for the doped electrolyte II (33 for I and 236 mu A/cm(2) for II). This effect can be related to the electrocatalytic effect of Co2+ cations.