Materials for improved lifetime of saggar in production of Li‐ion cathode powders

Abstract Ceramic saggars of mullite‐cordierite are currently used to produce cathode powders for lithium‐ion batteries. Strong interactions occur between the LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC) precursor in the temperature range of calcination (750–1000°C) leading to corrosion and formation of cracks in the saggar. The frequent failure of saggar causes a lot of waste, which could be reduced by choosing corrosion‐resistant materials. To understand the corrosion mechanism in the system MgO–Al 2 O 3 –SiO 2 , the materials MgO, Al 2 O 3 , MgAl 2 O 4 , and SiC (instead of SiO 2 ) were embedded in premixed NMC precursor and calcined at T = 780°C for 50, 100, 150 and 200 h. The formed phases were determined by phase and microstructure analysis. Finally, the formation of LiAlO 2 and Li 5 AlO 4 is associated with a lower growth rate of the corrosion layer compared with Li 4 SiO 4 , while MgO is inert. The reactivity with NMC can be ordered as follows: SiO 2 > Al 2 O 3 > MgO.