Effect of aliovalent doping on the electrical conductivity of the Li2SO4 - Na2SO4 binary

The effect of aliovalent doping (La3+) on the electrical conductivity of the 75: 25 and 10:90 Li2SO4 - Na2SO4 binary compositions is reported. While no significant conductivity enhancement is observed for the 75:25 composition, the sodium sulfate rich composition exhibits considerable enhancement, attributed to an increased vacancy concentration. For the 10:90 composition, the maximum enhancement is observed with 2 m/o La2(SO4)3 at 225oC and with 3 m/o La2(SO4)3 at 395oC. Interestingly, the Na2SO4 –rich and the Li2SO4 –rich compositions exhibit conductivity behavior consistent with that for pure Na2SO4 and pure Li2SO4, respectively.