Spray pyrolysis device with microwave heating and method for preparing ternary precursor thereof

Abstract

The invention provides a spray pyrolysis device with microwave heating and a method for preparing a ternary precursor thereof. The spray pyrolysis device comprises a microwave heating unit and a sintering unit from top to bottom; wherein the cavity of the microwave heating unit is provided with at least one set of microwave generator module. The method comprises the following steps: spraying ionized water into the spray pyrolysis device through an atomizing device, sequentially starting microwave generators of an evaporation zone, a drying zone and a thermal decomposition zone, switching the deionized water to a ternary precursor mixed solution after the temperature of the midpoint in the horizontal direction of each zone reaches a set value, and carrying out spray pyrolysis to obtain theternary precursor powder. By microwave heating for the evaporation zone, the drying zone and the thermal decomposition zone of the spray pyrolysis device, the problems of hollowing and breaking of secondary particles of the precursor prepared by spray pyrolysis are fundamentally solved, and favorable conditions are created for the preparation of the ternary precursor having high tap density, smallspecific surface area and low chloride content.

Description

technical field [0001] The invention belongs to the technical field of lithium battery materials, in particular to the field of preparation of lithium-ion battery anode material precursors, and relates to a spray pyrolysis device and a method for preparing a ternary precursor using the spray pyrolysis device, in particular to a spray pyrolysis with microwave heating The device and the method for preparing the ternary precursor by using the same can also be used for preparing other spherical solid secondary particle materials. Background technique [0002] Compared with the liquid phase precipitation method to prepare ternary material precursors, the spray pyrolysis method has the advantages of short preparation time, large output, low cost, no pollution, adjustable particle size, narrow particle size distribution, easy doping and uniform element distribution Easy to control and other advantages, it is a lithium-ion battery precursor preparation technology with great developm...

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Problems solved by technology

[0012] Using the above methods 1-3 can only obtain spherical solid secondary particles with an average particle size of less than 3 μm, and cannot produce solid secondary particle ternary material precursors with an average particle size of 3 to 15 μm, and the amount of additives added is generally Larger, not only increases the cost of raw materials, but also needs to consume more heat to complete the thermal decomposition reaction, and the subsequent high-temperature calcination to prepare the secondary particle shape of the spherical ternary material no longer maintains, resulting in a decrease in the tap density of the product. Increased chloride content (generally Cl>2000ppm)

However, the precursor material prepared by the second spray pyrolysis method in method 4 needs to add a spray pyrolysis process, which has high energy consumption and low output. Compared with the liquid deposition method, it does not have a cost-effective advantage.

[0013] Reference 8 (CN106587172A) discloses a production process and production device for a positive electrode ternary oxide of a power battery. The positive electrode ternary oxide of a lithium battery is prepared by spraying and pyrolyzing a chloride salt raw material solution, and the atomizer adopts a two-fluid (i.e. Two-fluid) aerosol nozzle or pressure nozzle, liquefied gas is used as heating fuel, and the droplets pass through the evaporation zone and drying zone from top to bottom in the spray pyrolysis tower, and then enter the roasting zone with a temperature of 780℃~1100℃ for decomposition. into ternary oxide and hydrogen chloride, the top pressure of the furnace is controlled at -200Pa, and the positive electrode ternary oxide is prepared, and then discharged through the discharge equipment at the bottom of the roasting area, and then dechlorinated by the dechlorinator to obtain the ternary oxide powder. The patent does not mention the physical and chemical indicators of the prepared ternary oxide powder, such as particle shape, particle size and distribution, tap density and Cl root content, etc.

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