5. The method of claim 1, wherein an average particle diameter (D50) of the transition metal precursor is greater than 10 μm, the temperature of the first temperature holding section is in the range of 500° C. to 650° C.
the transition metal precursor
average particle diameter (D50
greater than 10 μm
μm
the first temperature holding section
temperature
in the range of 500° C. to 650° C
° C