LITHIUM IRON PHOSPHATE HAVING AN OLIVINE STRUCTURE AND ANALYSIS METHOD THEREOF

摘要

The present invention relates to a lithium iron phosphate having an olivine crystal structure, and more particularly, to an olivine lithium iron phosphate which has compositions of chemical formula (1) Li1+a Fe1-x Mx(PO4-b) Xb (where M, X, a, x, and b are as defined in the specification), contains 0.1~5 wt % of Li3PO4, and contains no or less than 0.25 wt % of Li2CO3. The lithium iron phosphate according to the present invention contains no lithium carbonate or an extremely small amount of lithium carbonate, and contains Li3PO4 which is very electrochemically stable and excellent in thermal safety and ionic conductivity. Thus, the lithium iron phosphate of the present invention shows superior stability during high temperature and storage conditions, and improved safety and rate capability when used as positive electrode active material for a lithium secondary battery.