CN-121992473-A - Synthesis method for preparing monocrystal-like spherical lithium-rich manganese-based positive electrode material precursor by solid state precipitation method

CN121992473ACN 121992473 ACN121992473 ACN 121992473ACN-121992473-A

Abstract

The invention discloses a synthesis method of a monocrystal-like spherical lithium-rich manganese-based positive electrode material precursor by utilizing a solid-state precipitation method, which comprises the following steps of (1) a complexation mixing step, a precipitation reaction and aging/heat treatment step, wherein a nickel source, a cobalt source, a manganese source and a complexing agent are premixed in a powder form, the mixing temperature is 0-750 ℃, the mixing time is 10min-2h, the rotating speed is 100rpm-400rpm, a precipitation agent is added into the mixture of the step (1), the reaction is carried out for 10min-100h in a wide temperature range from room temperature to 950 ℃, and the post-treatment step is carried out, wherein the initial precursor is washed and filtered by deionized water, and a filter cake is dried for 10h at 120 ℃ to obtain the lithium-rich manganese-based precursor. The invention solves the technical bottlenecks of uneven element distribution, serious cation mixing and discharge, disordered growth of primary particles, low tap density and the like existing in the traditional coprecipitation method for preparing the material, and realizes excellent structural stability and cycle life like single crystal materials while maintaining excellent manufacturability of spherical particles.

Inventors

CHEN SHANHU
XIA LIANGHUI
ZHU MEIHUA
HE WENJING
ZHOU SILIN
TANG YUNFU

Assignees

江苏正旭企新材料有限公司

Dates

Publication Date: 20260508
Application Date: 20260114

Claims (4)

1. The synthesis method for preparing the monocrystal-like spherical lithium-rich manganese-based positive electrode material precursor by using the solid state precipitation method is characterized by comprising the following steps of: (1) Complexing and mixing, namely premixing a nickel source, a cobalt source and a manganese source with a complexing agent in a powder form, wherein the mixing temperature is 0-750 ℃, the mixing time is 10min-2h, and the rotating speed is 100-400 rpm; (2) A precipitation reaction and aging/heat treatment step of adding a precipitant into the mixture of the step (1) and reacting for 10min-100h at a wide temperature range of room temperature to 950 ℃; (3) And the post-treatment step is that the initial precursor is washed and filtered by deionized water, and the filter cake is dried for 10 hours at 120 ℃ to obtain the lithium-rich manganese-based precursor.
2. The method for synthesizing the monocrystal-like spherical lithium-rich manganese-based positive electrode material precursor by using the solid state precipitation method as claimed in claim 1, wherein the mixing equipment in the step (1) is a stirring kettle, a VC mixer or a pulverizer.
3. The method for synthesizing the monocrystal-like spherical lithium-rich manganese-based positive electrode material precursor by using the solid state precipitation method as claimed in claim 1, wherein the nickel source in the step (1) is nickel sulfate hexahydrate, nickel nitrate hexahydrate or nickel chloride; the cobalt source is cobalt sulfate heptahydrate, cobalt nitrate hexahydrate or cobalt chloride; The manganese source is manganese sulfate monohydrate, manganese nitrate tetrahydrate or manganese chloride; the complexing agent is one or more of gluconic acid, citric acid monohydrate, tartaric acid, anhydrous oxalic acid, ethylenediamine tetraacetic acid, urea and ammonium carbonate; the precipitant is one or more of sodium carbonate, sodium hydroxide and sodium bicarbonate.
4. The method for synthesizing a single crystal-single crystal like spherical lithium-rich manganese-based positive electrode material precursor by a solid state precipitation method according to claim 3, wherein the complexing agent is preferably an organic acid containing no nitrogen element, and is selected from the group consisting of gluconic acid, citric acid monohydrate, tartaric acid and combinations thereof.

Description

Synthesis method for preparing monocrystal-like spherical lithium-rich manganese-based positive electrode material precursor by solid state precipitation method Technical Field The invention relates to the technical field of batteries, in particular to a method for synthesizing a monocrystal-like spherical lithium-rich manganese-based positive electrode material precursor by a solid-state precipitation method. Background The lithium ion battery is used as a new generation energy storage device and has wide application prospect in the fields of electric automobiles and large-scale energy storage. However, the specific discharge capacity of the existing commercial cathode materials (such as lithium iron phosphate, ternary materials and the like) is generally lower than 200mAh/g, and the increasing demands of the market on high-energy-density batteries are difficult to meet. The lithium-rich manganese-based positive electrode material (Li-RICHMANGANESE-basedOxide, LRMO) is considered as one of the positive electrode materials with the most potential of the next-generation high-energy-density lithium ion battery due to the ultrahigh specific discharge capacity (> 250 mAh/g) and high operating voltage. From the standpoint of material structure design, there are two main technical routes at present, namely a first, polycrystalline spherical secondary particle structure. The structure is usually prepared by a coprecipitation method, has the advantages of high tap density and good electrode processing performance, and is the main form of current commercial application. Such as patent CN118954633a, a lithium-rich manganese-based positive electrode material with higher tap density, high capacity and high cycle performance is obtained through a coprecipitation-sanding-spraying process. However, the spherical particles are subjected to complicated processes such as spraying, and the cost is high. And the quasi-sphere is usually formed by agglomerating innumerable nano primary particles, and microcracks are easily generated in the secondary particles under the repeated action of cyclic stress. These microcracks can expose new active surfaces, exacerbate electrolyte side reactions, and provide channels for transition metal ion dissolution, thereby accelerating structural failure and performance decay of the material. The second route is to build up a single crystal grain structure. The structure effectively inhibits the generation of microcracks by eliminating grain boundaries, and shows excellent cycle stability and voltage holding capacity. For example, in the patents CN120774477a and CN120841588A, after preparing the transition metal salt into hydroxide by liquid precipitation, mixing with lithium source, and roasting to obtain the lithium-rich manganese-based anode material. However, the preparation of single crystal materials typically requires high temperature sintering or complex molten salt processes, which are costly and difficult to control. More importantly, the single crystal material is generally low in tap density, which is not beneficial to the improvement of the energy density of the electrode, and meanwhile, the compact bulk phase structure of the single crystal material also limits the bulk diffusion kinetics of lithium ions, so that the rate performance is often not ideal. In summary, the existing polycrystalline spherical structure is favorable for industrialization but has insufficient structural stability, while the single crystal structure has excellent stability but faces the bottleneck of difficult preparation and poor rate capability and processability. Therefore, an innovative material structural design is urgently needed, and excellent structural stability and cycle life like single crystal materials can be synchronously realized on the premise of keeping excellent manufacturability of spherical particles. Disclosure of Invention The invention aims to solve the technical problems of providing a synthesis method for preparing a monocrystal-like spherical lithium-manganese-rich positive electrode material precursor by utilizing a solid-state precipitation method, solving the technical bottlenecks of uneven element distribution, serious cation mixing, disordered growth of primary particles, low tap density and the like existing in the traditional coprecipitation method for preparing the material, and realizing excellent structural stability and cycle life as the monocrystal material while maintaining excellent manufacturability of spherical particles. In order to solve the technical problems, the invention provides a synthesis method for preparing a monocrystal-like spherical lithium-rich manganese-based positive electrode material precursor by using a solid-state precipitation method, which comprises the following steps of: (1) Complexing and mixing, namely premixing a nickel source, a cobalt source and a manganese source with a complexing agent in a powder form, wherein the mixing temperature i