Large Planar Na-β″-Al2O3 Solid Electrolytes for Next Generation Na-Batteries

Large diameter (> 100 mm) planar Na-β″-Al2O3 solid electrolytes (BASE) with thickness from 1.0 to 1.5 mm have been prepared. Na-β″-Al2O3 was processed as a slurry and cast to give several meters of tape. One hundred and forty mm diameter discs were punched from the tape, stacked, and laminated with a large hydraulic press. Binder burnout and sintering were performed in 150 mm diameter MgO spinel encapsulations to mitigate the loss of Na2O vapor. Conductivity and flexural strength were measured on smaller Na-β″-Al2O3 samples produced via the same tape casting process followed by sintering and gave results consistent with BASE materials produced by uniaxial pressing of powders. Planar BASE membranes enable new cell designs, which are predicted to have higher power densities and better stacking efficiency compared to currently manufactured tubular cells.

Organic Binder Burnout in Alumina Processing

Incomplete binder removal may introduce severe defects during ceramic processing. This work presents a new method to eliminate polyethylene glycol used as a binder in pre-sintering steps of alumina parts. The effectiveness of the proposed method was evaluated by density and pore size measurements, as well as thermogravimetry (TG), differential thermal analysis (DTA), volumetric physical adsorption analyzer (BET), and Fourier transformed infrared spectroscopy (FTIR). The results show that the new method, although relatively slow in comparison with traditional procedures, yields smaller pore sizes and better mechanical properties of the final products.

Preparation of Barium Titanate Grain-Oriented Ceramics by Electrophoresis Deposition Method under High Magnetic Field Using Single-Domain Nanoparticles

Barium titanate (BaTiO3, BT) grain-oriented ceramics were prepared by electrophoresis deposition (EPD) method under high magnetic field (HM-EPD) of 12 T. For this objective, the BT single-domain nanoparticles with highc/aratio of 1.008 and size of 103 nm were prepared by two-step thermal decomposition method. Using the BT nanoparticle slurry, BT nanoparticle accumulations were prepared by EPD or slipcasting (SC) methods with/without high magnetic field. After binder burnout, these accumulations were sintered at 1350 °C and it was revealed that only the BT ceramics prepared by the HM-EPD method was assigned to grain-oriented ceramics with weak preferential crystallographic orientation along [11 direction.