Method for synthesizing ammonium dihydrogen phosphate compound

Abstract

The invention discloses a method for synthesizing an ammonium dihydrogen phosphate compound. The method comprises the following steps: dissolving ammonium dihydrogen phosphate in deionized water, preparing a super-saturated solution at a certain temperature, dissolving organic sugar in deionized water, preparing an organic sugar solution with a certain mass percent at the temperature, uniformly mixing the two solutions in a stirring state, and standing for later use; and adding the mixed solution into an organic solvent in a stirring state according to a certain speed, standing at room temperature after the addition is finished, filtering to obtain a crystallized product, drying the obtained crystallized product at low temperature, and preparing to obtain the ammonium dihydrogen phosphate compound. According to the invention, ammonium dihydrogen phosphate and organic sugar can be mixed on the molecular scale, and the method has the characteristic that the phase distribution is uniform, so that a phenomenon that the carbon cladding is non-uniform due to non-uniform mixing of a carbon source in the process of synthesizing lithium iron phosphate in an organic solvent system by taking ammonium dihydrogen phosphate as a raw material.

Description

technical field [0001] The invention relates to a preparation process for synthesizing lithium iron phosphate raw materials for lithium battery cathode material, in particular to a synthesis method of ammonium dihydrogen phosphate compound, Background technique [0002] Lithium iron phosphate material is recognized as the safest lithium-ion battery cathode material, and is widely used in energy storage equipment, power tools, automotive power batteries, mobile power supplies, etc. Due to the poor ion conductivity of the lithium iron phosphate material itself, the deintercalation speed of lithium ions is not ideal during the charging and discharging process, which affects its electrochemical performance. At present, it is mainly electrochemically modified by carbon coating, doping and other methods. sex. In the electrochemical performance of carbon-coated modified lithium iron phosphate materials, the preferred carbon source is organic sugars, especially sucrose and glucose,...

AI Technical Summary

Problems solved by technology

In the electrochemical performance of carbon-coated modified lithium iron phosphate materials, the preferred carbon source is organic sugars, especially sucrose and glucose, but when ferrous oxalate is used as the iron source, organic solvents (especially absolute ethanol and acetone) In the process route of synthesizing lithium iron phosphate in the system, there is uneven carbon coating caused by the uneven mixing of the added carbon source. Uneven dispersion. At the same time, because the grinding equipment uses low-temperature cooling water to reduce the large amount of heat energy generated during the grinding process, the temperature of the grinding slurry is lower, which makes the sugars not suitable for dissolution and dispersion, and finally leads to the appearance of uneven carbon coating.

Carbon coating is one of the commonly used methods in the modification of lithium iron phosphate, but due to the carbon addition method and uneven coating, the synthesized lithium iron phosphate is unstable in batches in terms of carbon content, which affects the processing of materials performance