A kind of preparation method of lithium iron phosphate electrode material

Abstract

The invention discloses a preparation method of an LFP material. The preparation method comprises the following steps of (1) feeding the raw materials for preparing the LFP material into a smelter, then heating the raw materials into a molten state and enabling the molten raw materials to flow out; (2) quenching the out-flow molten materials in water and then drying the quenched materials; (3) performing superfine processing and then carbon coating on the dried materials. The preparation method of the LFP electrode materials can achieve continuous production of the LFP material and meanwhile is stable in quality and low in energy consumption. Compared with an existing liquid phase method capable of achieving mass production, the preparation method of the LFP electrode material is equivalent in physical and chemical performance index but simpler in production process, free from restriction of water solubility, lower in energy consumption and production cost and applicable to a mass production non-heavy waste water treatment process; compared with a solid phase method, the preparation method of the LFP material is complete in reaction degree, high in production efficiency and obvious in enhancement of physical and chemical performance indexes. By contrast, the solid phase method lags in technology and falls into disuse. Technological processes and equipment utilized in the preparation method of the LFP material are mature and well-used, thereby facilitating control and adjustment of production processes and product quality.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, and in particular relates to a preparation method of a lithium iron phosphate electrode material. Background technique [0002] Lithium iron phosphate (molecular formula LiMPO 4 , LithiumIronPhosphate, also known as lithium iron phosphate, lithium iron phosphorus, referred to as LFP), is a positive electrode material for lithium ion batteries, also known as lithium iron phosphorus batteries. Lithium and iron are rich in resources on the earth, so there will be no problem of supply. It has moderate working voltage (3.2V), large capacity (170mAh / g), high discharge power, fast charging and long cycle life, and high stability in high temperature and high heat environment. [0003] As a high-performance secondary green battery, lithium-ion battery has high voltage, high energy density (including volume energy, mass energy), low self-discharge rate, wide temperature range, long cycle life, enviro...

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Problems solved by technology

[0005] At present, its preparation methods mainly include solid-phase method and liquid-phase method. The solid-phase method is still the most commonly used synthetic method. It uses mechanical methods to physically mix the particles of the initial raw materials, and then pushes the furnace in a nitrogen-protected pusher furnace. , Rotary furnace, etc. to produce by sintering; because the raw material particles are in solid phase contact, the contact area and the degree of sintering reaction are quite limited, making the reaction speed slow, the production cycle is long, and the output is low; the liquid phase method is now emerging A kind of synthesis method, all the raw materials used in the synthesis must be water-soluble, so that the molecular contact between the raw materials can be realized, and it is carried out in a closed reaction kettle; the biggest advantage of the liquid phase method is that it can prepare ultrafine particles, so The product of the contact reaction between molecules can reach the nanoscale; at the same time, the raw materials are soluble in water, and the raw material molecules can diffuse rapidly to achieve uniformity, so it can be produced at a relatively low reaction temperature; but its equipment investment Large, complex process, relatively low output, wastewater treatment in the production process also requires complicated processes and equipment

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