Recently, active research has been conducted to enhance the power characteristics and thermal stability of lithiumion batteries (LiBs) by modifying separators using a ceramic coating method. However, since the thermal properties and surface features of the separator vary depending on the characteristics of the ceramic powders applied to the separator, it is crucial to manufacture ceramic powders optimized for the separator’s performance. In this study, we evaluated the characteristics of three types of α-alumina (A-1, A-2, and A-3) produced with varying dispersant contents and milling times, in addition to commercial α-alumina (AES-11). Subsequently, the optimized powders (A-3) were coated onto the separator using an aqueous binder for comparison with the characteristics of an AES-11 coated separator and an uncoated PE separator. The A-3 coated separator improved electrolyte wettability with a low contact angle (44.69°) and increased puncture strength (538 gf). Furthermore, it exhibited excellent thermal stability, with a shrinkage value of 5.64% when exposed to 140℃ for 1 hour, compared to the AES- 11 coated separator (6.09%) and the bare PE separator (69.64%).

The effects of compaction methods on the sintering density, microstructures, and mechanical properties were investigated in α-alumina ceramics. α-Alumina powders were granulated with a 10% aqueous solution of polyvinyl alcohol (PVA). Uniaxially pressed (UAP) and cold isostatic-pressed (CIP) samples were prepared by pressing uniaxially at a pressure of 1 ton for 1 min, and isostatically at 200 MPa for 15 min, respectively. Subsequently, both types of samples were sintered at 1,200℃, 1,300℃, 1,400℃, 1,450℃, 1,500℃, 1,550℃, and 1,600℃ at a rate of 5℃/min for 2 h. The CIP samples were better than the UAP samples for all properties measured, such as the sintering density, Vicker’s hardness, and toughness. The CIP sample sintered at 1,400℃ showed the maximum Vicker’s hardness and toughness; this may be attributed to the competing effects of a decrease in porosity and the growth of grains with increasing sintering temperature.