| 摘要 |
PROBLEM TO BE SOLVED: To provide a positive electrode material for lithium secondary battery, by which a lithium secondary battery can be obtained which shows stable battery performance due to an olivine type lithium manganese iron phosphate of which the surface is coated with carbon hardly absorbing moisture.SOLUTION: A positive electrode material for lithium secondary battery is obtained by: mixing an olivine type lithium manganese iron phosphate compound and graphite in the proportion of (olivine type lithium manganese iron phosphate compound: graphite) 99:1-91:9 on a mass basis; and baking the resultant mixture at 460-790°C in a reducing atmosphere or inactive atmosphere. In the case that the material is left adsorbing moisture under the condition of a temperature of 20°C and a relative humidity of 50% until reaching its equilibrium, then the temperature of the material is raised to 250°C and further, the material is kept at the temperature for 20 minutes, and a moisture adsorption amount measured as an amount of moisture volatilized during a period of time from the time of the achievement of equilibrium to the time when the 20 minutes has elapsed is 2100 ppm or less.SELECTED DRAWING: None |
