Tape casting is a well-established shaping technique for ceramic materials and can be scaled up with existing experience. Recently we started the preparation of dense electrolyte sheets for Li-ion batteries. Sol-gel prepared nano-sized powder of Li1.5Al0.5Ti1.5(PO4)3 [1] was successfully tape-cast using the doctor blade method. Plain sintered sheets with thicknesses between 50 µm and 150 µm could be fabricated with a maximum size of 10 cm². The densification and ionic conductivity at different sintering temperatures were investigated by microstructural analysis and impedance spectroscopy, respectively. The average total ionic conductivity was in the range of 0.2 mS/cm, which is still lower than powder pellets [1], but already twice as good as commercially available glass-ceramics [2]. The results show that the density and the microstructure are very sensitive to sintering temperatures and dwell time. The ionic conductivities and the sintered thicknesses are presented in Table 1. The highest ionic conductivity of 0.3 mS/cm is achieved at 1000°C sintering temperature. The parameters are actually under optimization with respect to higher density, better homogeneity and reduced crack formation. For the mechanical stability 4 point bending strength tests were carried out on samples sintered at 900°C with dimensions of h = 150 µm, b = 1 cm, l = 5 cm resulting in a modulus of elasticity of E = 67 GPa ±14 GPa, and a specific fracture resistance σb = 62 MPa ±7 MPa. The stability of these sheets is promising for further use in any battery design with ceramic separator.