Preparation Of Cordierite-mullite Composite Saggar For Firing Cathode Materials Of Lithium Ion Battery And Its Performance Of Resisting Corrosion

The ternary cathode material affected the service life of the saggar,which resulted from corrosion.In order to improve the performance of the saggar and the quality of the cathode material,the performance of the composite saggar and erosion mechanism against Li Ni_0.5Co_0.2Mn_0.3O₂（LNCM）was studied.The laboratory method was applied in the saggar enterprises to provide a reference for the actual production.With the molding pressure 150 MPa,the firing temperature 1420°C and the heat preservation 3h,the density and the porosity of saggar,consisting of 40%1～2mm cordierite,22.5%0～1mm cordierite,7.5%0～1mm mullite,25%matrix mullite and 5%yellow dextrin,were 1.83g/cm³and 28%respectively.To strengthen the performance,kaolin andα-Al₂O₃ were added to the experimental formula.The performance of the saggar was upgraded greatly by changing type and addition amount of matrix.The density and the porosity of the saggar were 1.9 g/cm³and 33%respectively.The flexural strength and the strength retention rate were 11.58MPa and 76%respectively.The best formula was consisted of 40%1～2mm cordierite,22.5%0～1mm cordierite,7.5%0～1mm mullite,25%α-Al₂O₃ and 5%yellow dextrin.The saggar eroded 25 times,with reaction layer of 100μm,the maximum permeable layer of 700μm and the widest part of the crack of 200μm,showed that Li₂O infiltrated into mullite and cordierite and formed Li Al O₂,Li Al Si O₄ and other substances of large thermal expansion coefficients.The volume effect and thermal expansion effect lead to the destruction of the saggar.The optimal condition of actual production was determined by orthogonal experiment of 5 factors and 4 levels.The produced saggar was used for the LNCM of synthesis.The safe service life has reached 30 times and the recycling rate has been increased by 20%.