An approach for tape casting and sintering of Li7La3Zr1.75Nb0.25Al0.1O12 (LLZNbO) sheets suitable for use in solid-state battery development is described. The use of Li3BO3 as a sintering aid in both pellet and cast tape samples is examined. We find the optimal Li3BO3 content for ionic conductivity in pellets is between 1 and 2 wt% Li3BO3, much less than in prior reports. At this level, ionic conductivity is similar to 2.5 x 10(-4) S cm(-1) after sintering in an argon atmosphere at 1000 degrees C for 6 h. 150-175 micron thick LLZNbO + 0.5% Li3BO3 tapes sintered at 1000 degrees C for 6 h exhibit ionic conductivity values of 2-3 x 10(-4) S cm(-1).