| abstract |
A container for heat treatment of a positive-electrode active material of a lithium ion battery to hold raw material powder of the positive-electrode active material of the lithium ion battery when the raw material powder is subjected to heat treatment is provided. The heat treatment container contains 60 to 95 mass % of alumina and 10 to 20 mass % of silica, is free from MgO, ZrO 2 and Li compounds, and has a porosity of 10 to 20%. The heat treatment container suppresses a reaction product from contaminating the raw material powder owing to suppressed reactivity with the raw material powder, and is suppressed from being cracked by thermal shock owing to the porosity in the predetermined range. |