关键词: 三元正极材料, 氢氧化锂, 堇青石-莫来石, 重结晶SiC, β-SiC结合SiC, 抗侵蚀性

Abstract: In order to get sagger material with high alkali resistance and suitable for ternary cathode material,LiOH·6H₂O was placed on the surface of recrystallized SiC sagger material and β-SiC bonded SiC sagger material,respectively,to investigate their corrosion at 780 ℃ for 20 h in oxygen atmosphere.The two sagger materials were compared with the commercial cordierite-mullite saggar material.The microstructure and the phase composition of the three materials were analyzed by SEM and XRD.The results show that:(1)a reaction layer with a thickness of 4.2 mm is formed on the surface of β-SiC bonded SiC material after corrosion; there is no obvious reaction layer on the surface of the recrystallized SiC material; the surface of cordierite-mullite material becomes uneven,and a reaction layer with a depth of about 1.8 mm is formed below the surface;(2)the density of sagger materials can significantly affect the penetration depth of Li₂O;the β-SiC bonded SiC material is denser and the penetration of Li₂O is shallower;the volume expansion caused by the reaction seriously damages the surface structure of the material;(3)the apparent porosity and the pore size of the recrystallized SiC material are larger than those of the β-SiC bonded SiC material,Li₂O can penetrate into the recrystallized SiC more easily and form Li₂SiO₃ in the internal pores,but the overall structure of the material is not affected obviously.

Key words: ternary cathode material, lithium hydroxide, cordierite-mullite, recrystallized SiC, β-SiC bonded SiC, corrosion resistance