A production method of anhydrous iron phosphate and its special molding tool

Abstract

The invention relates to a production method of anhydrous iron phosphate and a special molding tool thereof. The production method is to mold the ferric phosphate dihydrate powder filled in a sagger, evenly arrange a plurality of heat-conducting air holes, and then heat the mold at 580°C After roasting and dehydration at ‑630°C, anhydrous iron phosphate with small specific surface area can be obtained. The tool includes a sagger and a model matching the sagger; the model includes a mold cover, a mold column and a handle; the mold column is evenly arranged on the bottom of the mold cover and has the same height as the depth of the sagger cavity; the handle is fixed on the mold The top of the cover; when the powder is molded, the mold cover is matched with the upper end of the cavity of the sagger, and the mold column is inserted into the powder and extends to the bottom of the cavity. This method conducts the heat transfer path and reduces the attenuation gradient, thereby achieving a high dehydration rate and ensuring a small specific surface area. The special molding tool has simple and reasonable structural design, high molding efficiency, and can effectively improve production efficiency.

Description

technical field [0001] The invention belongs to the technical field of lithium ion battery materials, and relates to the improvement of the specific surface area of ​​anhydrous iron phosphate, a positive electrode precursor material of lithium ion batteries. Anhydrous iron phosphate is the main raw material of lithium iron phosphate, the positive electrode material of lithium ion power batteries. It has a very high water absorption rate, which affects the safety of lithium iron phosphate batteries; in order to reduce the water absorption rate of anhydrous iron phosphate, thereby improving its specific surface area, the water absorption rate of lithium iron phosphate, the lithium battery material of the anhydrous iron phosphate, is correspondingly higher Low. Background technique [0002] At present, anhydrous iron phosphate is the main raw material of lithium iron phosphate, the cathode material of lithium-ion power batteries. Anhydrous iron phosphate has strong water absorp...

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Problems solved by technology

[0004] During the roasting process, the container (saggar) transfers heat more slowly in the powder accumulation, especially the central part, and the water vapor of ferric phosphate dihydrate (powder) is difficult to escape from the powder during the dehydration process, and the dehydration rate is small. The specific surface area of ​​the powder after sintering in the center of the container (saggar) is as high as 30m2 / g, and the specific surface area of ​​anhydrous iron phosphate in the container (saggar) fluctuates greatly; The powder on the surface of the container (sagger) has been scorched (discolored), but there is still heat transfer attenuation in the center of the container (sagger), and the specific surface area of ​​the powder in the center of the container (sagger) is still large, so it is difficult to The specific surface area is reduced and restricts limited production efficiency

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