Study On Electrochemical Sensor Of Aluminum Solid Electrolyte (Al_0.2Zr_0.8)_20/19Nb（PO₄）₃

The (Al_0.2Zr_0.8)_20/19Nb（PO₄）₃solid electrolyte was synthesized by the coprecipitationmethod; Al₂（WO₄）₃solid electrolyte was synthesized by the coprecipitation and the sol-gel method. Added with different amount of ZnO, the phase composition, microstructureand electrical conducting property of samples are characterized by XRD, SEM and EIS,respectively. Studied the stability of (Al_0.2Zr_0.8)_20/19Nb（PO₄）₃and Al₂（WO₄）₃in500℃galvanizing zinc. Prepared Al sensor with (Al_0.2Zr_0.8)_20/19Nb（PO₄）₃and Al₂（WO₄）₃as thesolid electrolyte. The results show that::The different ZnO doping ratio have a great effect on the phase composition andmicrostructure. At a certain sintering temperature,(Al_0.2Zr_0.8)_20/19Nb（PO₄）₃was formed ofNASICON structure, and formed of Al₂（WO₄）₃pure phase structure, there is no impurityphase generation. There was no ZnO phase appeared, which showed ZnO reacted with(Al_0.2Zr_0.8)_20/19Nb（PO₄）₃and Al₂（WO₄）₃. The grain size and the density of samplesincrease with increasing the ZnO amount.The stability tests determined that (Al_0.2Zr_0.8)_20/19Nb（PO₄）₃and Al₂（WO₄）₃werestability in the galvanizing zinc, the diffraction peak intensity, peak shape and peakposition hardly change. The SEM showed the section of the samples was density withoutholes.The ion transference number tests determined that (Al_0.2Zr_0.8)_20/19Nb（PO₄）₃testedunder different voltage, the Al ion transference number were above0.99, which showedthat the main conduction ion is Al3+, electronic conduction can be ignored; Al₂（WO₄）₃tested under different voltage, the Al ion transference number were above0.96, whichshowed that the main conduction ion is Al3+, electronic conduction can be ignored.The (Al_0.2Zr_0.8)_20/19Nb（PO₄）₃with5%ZnO sintered at1300℃had the highestconductivity,1.24×10-3S·cm-1at700℃, Al₂（WO₄）₃was synthesized by thecoprecipitation method with1%ZnO sintered at1000℃, the highest conductivity was4.27×10-4S·cm-1at800℃，Al₂（WO₄）₃was synthesized by the sol-gel method with1%ZnO sintered at1000℃, the highest conductivity was2.55×10-4S·cm-1at800℃. TheAl sensor is prepared with (Al_0.2Zr_0.8)_20/19Nb（PO₄）₃and Al₂（WO₄）₃has the respond to theAl concentration in the hot zinc solution.