Lithium iron phosphate having an olivine structure and method for preparing the same

摘要

Provided is an olivine-type lithium iron phosphate having a composition represented by Formula I, comprising 0.1 to 5% by weight of Li 3 PO 4 , and comprising no Li 2 CO 3 or, if present, comprising Li 2 CO 3 in an amount less than 0.25% by weight: Li 1+a Fe 1-x M x (PO 4-b )X b (I) wherein M, X, a, x and b are as defined above. The lithium iron phosphate comprises no lithium carbonate (Li 2 CO 3 ) or, if present, comprises the Li 2 CO 3 in an extremely small amount, and comprises Li 3 PO 4 having superior electrochemical stability, thermal stability and ionic conductivity, thus advantageously imparting high-temperature and storage stability as well as stability and rate properties to lithium secondary batteries, when used as a cathode active material for the lithium secondary batteries.