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

The ion-exchange properties of NASICON type ceramics of composition Na3Zr2S i2PO12 were investigated in aqueous solutions of NaCl, LiCl and KCl. The so lution analysis shows that the [Zr2Si2PO12] framework strongly prefers Naion relative to K+ and Li+. The exchange current density of the alkali-cati ons at the NASICON/solution interface determined by impedance measurements varies in the order Na+ > Li+ > K+. These results agree well with the selec tivity coefficients of Na+ ion selective electrodes based on NASICON. The i nterference process to alkali-cations in the NASICON based electrode was sh own to result from an ionic exchange. The selectivity was suggested to be g overned by the mobility of the cation inside the NASICON framework. (C) 199 9 Elsevier Science Limited. All rights reserved.