A solution for semi-wet synthesis of polyanionic phosphate cathode materials

Abstract

The invention discloses a solution for synthesizing polyanionic phosphate cathode materials by a semi-wet method, which comprises the following components by mass percentage: 5.5%-10% of solute, 80-92% of solvent, and 2.5%-10% of solubilizer , the solute is a compound containing Li and P elements simultaneously; the solvent is a mixture of ethanol, n-butanol, isopropanol, butylene glycol and water, and its mixing ratio is ethanol: n-butanol: isopropanol by mass percentage : butanediol: water=5%-15%: 5%-8%: 2%-4%: 5%-9%: 64%-83%; the solubilizer is a surfactant. The solute is Li 3 PO 4 、LiPO 2 f 2 、LiPOF 3 One of. The invention can effectively solve the problem of raw material concentration segregation in the spray drying process of the precursor of the polyanionic phosphate positive electrode material, and has good solubilizing and dispersing effects on the solution insoluble components used for material modification.

Description

technical field [0001] The invention belongs to inorganic new energy materials, in particular to a solution for semi-wet synthesis of polyanionic phosphate cathode materials. Background technique [0002] The polyanionic phosphate cathode material represented by lithium iron phosphate has good cycle stability because of its stable anion structure. At present, most of the polyanionic cathode materials on the market are phosphate structures, such as lithium iron phosphate, phosphoric acid Lithium manganese, lithium vanadium phosphate, lithium manganese iron phosphate, etc. [0003] Above these polyanionic phosphate cathode materials, the method suitable for its industrial production is mainly solid-phase production process, but solid-phase method has a series of problems such as poor batch consistency and unstable quality in essence, and its preparation method Wet chemical methods such as hydrothermal method and sol-gel method are more suitable for small batch sample preparat...

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Problems solved by technology

[0003] Above these polyanionic phosphate cathode materials, the method suitable for its industrial production is mainly solid-phase production process, but solid-phase method has a series of problems such as poor batch consistency and unstable quality in essence, and its preparation method Wet chemical methods such as hydrothermal method and sol-gel method are more suitable for small batch sample preparation, although the consistency is very good. Therefore, in order to improve the problem of poor consistency caused by the solid phase method, the industry has successively developed spray Semi-wet Synthesis of Polyanionic Phosphate Cathode Materials Represented by Drying

[0004] Its main representative process is to mix transition metal oxides (or other types of transition metal salts) with lithium and phosphate-containing solutions, and then perform high-temperature spray drying. The quality consistency of the products obtained in this way is better than that of traditional solid-phase production. process, but the main problem of this method is that the solution system is likely to cause segregation of raw material concentration during the drying process, resulting in quality fluctuations. On the other hand, in order to achieve material modification, some modified ions are often added to the solution, but the improvement Sexual ions usually exist in the form of insoluble components, so that the mixing uniformity of the product precursor is reduced