Method for preparing lithium iron manganese phosphate by using waste lithium iron phosphate and lithium manganate materials

Abstract

The invention provides a method for preparing lithium iron manganese phosphate from waste lithium iron phosphate and a lithium manganate material. The method comprises the following steps: (1) recycling waste lithium manganate to obtain a filtrate A; (2) recycling the waste lithium iron phosphate to obtain filtrate B; (3) carrying out ICP (Inductively Coupled Plasma) test on the filtrate A and thefiltrate B to obtain the content of each main element in the two groups of filtrate; (4) the ratio of the filtrate A to the filtrate B is determined according to the mole number x + y = 1 of Fe and Mn elements in the two groups of filtrate, x is equal to (0.9-0.1), and y is equal to (0.1-0.9); supplementing a phosphorus source and a lithium source according to the required molar ratio of P, Li, Mn and Fe, and reacting to obtain a lithium ferric manganese phosphate precursor; and then carrying out high-temperature roasting thermal reaction to obtain the lithium iron manganese phosphate positive electrode material. The method provided by the invention is relatively simple in process and convenient to operate, the two waste raw materials are wide in source and low in price, the loss of resources and the addition of auxiliary materials can be reduced, the material recovery rate can be increased, and the cost of equipment, production, raw materials and the like can be reduced.

Description

technical field [0001] The invention relates to the preparation of lithium iron manganese phosphate positive electrode materials from lithium battery positive electrode recovery materials, and belongs to the field of battery material recovery. [0002] technical background [0003] With the extensive use of lithium-ion batteries, a large number of waste lithium-ion batteries have been generated. These waste batteries are eliminated because they cannot meet the corresponding energy storage needs. If these waste batteries are directly treated like other garbage, it is likely to cause serious environmental pollution, and there is also a potential fire hazard caused by battery short circuit. Therefore, recycling lithium battery waste has become necessary in order to recycle materials, save costs and protect the environment. [0004] Lithium manganese iron phosphate material relative to Li + The electrode potential of / Li is 4.1V, which is higher than the 3.4V of lithium iron p...

AI Technical Summary

Problems solved by technology

In this method, the adhesive is removed by roasting, so that lithium iron phosphate and aluminum foil are easily separated, and then the separated lithium iron phosphate is treated with acid leaching. After elemental analysis, phosphorus source, manganese source, lithium source, etc. are added, dried and sintered to obtain Lithium iron manganese phosphate, but too much iron source, phosphoric acid, lithium source, etc. need to be added in the treatment process, which cannot achieve the most effective recovery, save costs and protect the environment

[0007] The methods provided by the above-mentioned prior art all deal with a single waste positive electrode material, which needs to be prepared by adding a large amount of auxiliary materials, which increases the manufacturing cost and consumes more resources, cannot form economic benefits, and cannot promote the development of the field of battery material recycling. , and it is impossible to maximize the recycling of lithium battery cathode materials

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