Lithium iron phosphate positive electrode material, preparation method thereof and lithium ion battery

Abstract

This invention provides a lithium iron phosphate cathode material, its preparation method, and a lithium-ion battery. The preparation method includes: preparing a first slurry by mixing a first phosphorus source, a first iron source, a first carbon source, a first lithium source, and a first solvent; preparing a second slurry by mixing a second phosphorus source, a second iron source, a second carbon source, a second lithium source, and a second solvent; mixing the first and second slurries to obtain a third slurry; and obtaining the lithium iron phosphate cathode material after reaction and drying of the third slurry. In the first slurry, the molar ratio of phosphorus (P), iron (Fe), and lithium (Li) is N1; in the second slurry, the molar ratio of phosphorus (P), iron (Fe), and lithium (Li) is N2; N1 and N2 are not equal; both the first and second solvents include water, ethylene glycol, and an organic acid. This invention, by constructing reaction systems with different iron-phosphorus ratios and introducing organic acids into the reaction solvent system, ultimately prepares a lithium iron phosphate cathode material with higher compaction density and better discharge performance.

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