Micron Grade Alumina Powder Ceramic Coating Battery Separator Lithium ion batteries have emerged as the most popular energy storage system, but they pose safety issues under extreme temperatures or in the event of a thermal runaway. Lithium ion batteries with inorganic separators offer the advantage of safer operation.The coated α-Al2O3 separator has a much higher resistance to temperature effects than its polyolefin counterparts, retaining its dimensional integrity at