Ion exchange properties of NASICON-type ceramics - application to ion selective electrodes

摘要

The ion-exchange properties of NASICON type ceramics of composition Na_3Zr_2Si_2PO_(12) were investigated in aqueous solutions of NaCl, LiCl and KCl. The solution analysis shows that the [Zr_2Si_2PO_(12)] framework strongly prefers Na~+ ion relative to K~+ and Li~+. The exchange current density of the alkalications at the NASICON/solution interface determined by impedance measurements varies in the order Na~+>Li~+>K~+. These results agree well with the selectivity coefficients of Na~+ ion selective electrodes based on NASICON. The interference process to alkali-cations in the NASICON based electrode was shown to result from an ionic exchange. The selectivity was suggested to be governed by the mobility of the cation inside the NASICON framework.