Method for improving low-temperature performance of lithium iron phosphate anodic material for lithium batteries and lithium batteries

Abstract

The invention discloses method for improving the low-temperature performance of a lithium iron phosphate anodic material for lithium batteries and lithium batteries. The method is to add lithium cobaltate into the formula of the lithium iron phosphate anodic material for lithium batteries. In the invention, based on the characteristic that the low-temperature discharging performance of the lithium cobaltate is high, the problem of low-temperature performance of the conventional lithium iron phosphate batteries is solved, the conventional production process is not changed, and the lithium iron phosphate batteries with high low-temperature performance are manufactured. In the invention, by optimizing and screening the added amount of lithium cobaltate, the low-temperature discharging volume retention rate is increased, the discharging time is prolonged, and better effect is obtained.

Description

technical field [0001] The invention relates to a preparation method of lithium iron phosphate, a positive electrode material of a lithium battery, in particular to a method for improving the low-temperature performance of lithium iron phosphate, a lithium iron phosphate positive electrode material of a lithium battery, and the obtained lithium battery prepared by the method. Background technique [0002] At present, lithium batteries have been widely used due to their advantages of light weight, high energy density, small self-discharge, long life, high discharge power and environmental protection. [0003] Lithium batteries include four major materials: positive electrode, negative electrode, diaphragm, and electrolyte. Among them, the positive electrode material is the most critical raw material in lithium batteries, which determines the safety performance of the battery and whether the battery can be large-scaled, accounting for about 10% of the cost of lithium battery ce...

AI Technical Summary

Problems solved by technology

[0004] In comparison, lithium cobalt oxide has poor safety, high cost, and short cycle life. Although the safety of lithium manganese oxide is better than that of lithium cobalt oxide, the cycle life is worse in high temperature environments. Lithium iron phosphate has high discharge power and low cost. , fast charging and long cycle life, high stability in high temperature and high heat environment, and good safety performance, so it is selected as the positive electrode material of lithium batteries and is widely used in EV, HEV, PHEV, electric bicycles and other fields

[0005] However, one disadvantage of lithium iron phosphate is that its own electronic conductivity is very low, especially at low temperatures (usually below -20°C), lithium iron phosphate almost becomes a non-conductive insulator, so that lithium iron phosphate batteries can be used at low temperatures barely work

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