Low-temperature lithium iron phosphate positive electrode material prepared by uniform coating using modified flash device and preparation method thereof

Abstract

The invention relates to a low-temperature lithium iron phosphate positive pole material capable of implementing uniform coating preparation by a modification flash distillation plant and a preparation method thereof. The method comprises the following steps: preparation of manganese iron phosphate precursor: proportionally and sufficiently mixing a phosphorus source, an iron source and a manganese source, pelleting, and dehydrating and presintering at 500-600 DEG C to obtain a manganese iron phosphate precursor; preparing water or a water-organic solvent mixed solution, adding the mixed solution, sufficiently crushing, and stirring for 3-5 hours; starting a microwave source and a bottom orthogonal gas valve on of the modification flash distillation plant, and spraying the stirred slurry into the modification flash distillation plant by a sprayer through a pipeline after being treated by a pressure pump on the bottom of the stirring vessel; and carrying out 300-750-DEG C gradient thermal-insulation sintering according to the particular coating material to obtain the coated lithium iron phosphate positive pole material.

Description

technical field [0001] The invention relates to a battery positive electrode material and a preparation method thereof, in particular to a low-temperature lithium iron phosphate positive electrode material prepared by uniform coating using a modified flash evaporation device and a preparation method thereof. Background technique [0002] Lithium-ion battery cathode material is an important part of green and environment-friendly lithium battery, and lithium-ion battery is an important new energy technology to deal with the depletion of energy and the deteriorating environment in the 21st century; so whether the performance of lithium-ion battery cathode material is superior or not It directly determines the use quality and performance of lithium-ion batteries; while the traditional method of preparing lithium-ion battery cathode materials generally uses solid-state technology, which has relatively large shortcomings in controlling the uniformity of material element distributio...

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Problems solved by technology

[0002] Lithium-ion battery cathode material is an important part of green and environment-friendly lithium battery, and lithium-ion battery is an important new energy technology to deal with the depletion of energy and the deteriorating environment in the 21st century; so whether the performance of lithium-ion battery cathode material is superior or not It directly determines the use quality and performance of lithium-ion batteries; while the traditional method of preparing lithium-ion battery cathode materials generally uses solid-state technology, which has relatively large shortcomings in controlling the uniformity of material element distribution and quality consistency. And it is difficult to achieve effective control of the particle size distribution of materials, resulting in the quality and performance of domestic lithium battery cathode materials have been lagging behind developed countries

[0003] The solid-phase method is the main method for the synthesis of positive electrode materials for batteries. It is simple to operate and easy to industrialize. However, it is difficult to control the degree of uniformity of raw materials. Reactor-type hydrothermal preparation is mostly used in the phase process, and the special properties of supercritical water under high temperature and high pressure are used to realize the synthesis of materials. The finished materials obtained by the liquid phase method are uniform in size and small in primary particle size, and can obtain nano-scale lithium-ion battery cathode materials. , but the operation of the liquid phase process is complicated, and the conditions of high temperature and high pressure put forward higher requirements for the reaction equipment, which is not conducive to mass production and has potential safety hazards

[0004] Due to the low intrinsic conductivity and poor discharge performance of iron phosphate materials, the ambient temperature severely restricts the application of lithium iron phosphate batteries. Although external devices such as antifreeze clothing can alleviate the impact of lower temperatures on material performance to a certain extent. However, it is still unable to meet the stability of lithium iron phosphate lithium-ion batteries in cold regions. At the same time, common material modification methods such as coating and doping are too cumbersome to produce, and they often lose sight of others.

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