High-Nickel Cathode Preparation with Liquid-Phase Lithium Coating
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Solution Overview
Problem
High-nickel ternary cathode materials face issues such as microcracks due to volume changes, difficulty in mass transfer due to large pores, material degradation from electrolyte invasion, and poor cycle performance.
Innovation Solution
A preparation method involving primary sintering of a LiOH powder with a high-nickel ternary precursor in an oxygen atmosphere, followed by liquid-phase lithium supplementation and coating with ionic conductors like Li2MoO4, Li2WO4, or Li2SnO3, and finally coating with boric acid and tempering to enhance uniformity and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If solid-phase mixing and high-temperature sintering is used for substrate sintering, then the process is simple and feasible, but it is difficult to ensure thorough mixing of precursor and lithium source, resulting in uneven growth of primary particles
Solution Approach 1:
The patent introduces a liquid-phase intermediate (aqueous solution containing lithium salt and metal oxide) as a mediator between the precursor and final sintered product. This liquid intermediary enables uniform distribution of lithium and coating materials throughout the precursor particles during low-temperature sintering, solving the mixing uniformity problem while maintaining process simplicity
Solution Approach 2:
The patent changes the physical state parameter from solid-phase to liquid-phase during the intermediate processing stage. By dissolving lithium salt and metal oxide in water to form a uniform solution, then applying this solution to the precursor, the method achieves homogeneous distribution that cannot be obtained through solid-phase mixing alone
2Ease of manufacture
If solid-phase mixing and high-temperature sintering is used for coating modification, then the process is simple, but it is difficult to ensure uniformity of the coating layer, causing partial over-thick coating or no coating
Solution Approach 1:
The patent uses an aqueous solution containing metal oxide as a liquid intermediary for coating application. This liquid medium allows the coating material to be uniformly distributed and deposited on the particle surfaces during low-temperature sintering, eliminating the coating uniformity problems associated with solid-phase mixing
Solution Approach 2:
The patent replaces the mechanical mixing approach with a chemical dissolution-deposition mechanism. Instead of mechanically mixing solid coating materials with precursors, the method dissolves coating materials in water, applies the solution, and then uses controlled sintering to deposit a uniform coating layer
3Quantity of substance
If high-nickel ternary material is used, then specific capacity increases, but microcracks are easily caused by volume changes in cycle process
Solution Approach 1:
The patent creates a composite structure by coating nickel-rich particles with metal oxide layers (such as cobalt oxide, manganese oxide, or mixed oxides). This composite structure maintains the high capacity of the nickel-rich core while the oxide coating provides structural stability and crack resistance during cycling
Solution Approach 2:
The patent applies a protective metal oxide coating layer before the material undergoes cycling. This pre-applied coating acts as a cushioning layer that absorbs and distributes the mechanical stress from volume changes, preventing microcrack formation in advance
4Quantity of substance
If high-nickel ternary material is used, then specific capacity increases, but mass transfer is difficult due to large pores between primary particles
Solution Approach 1:
The patent applies different properties to different regions: the core maintains high nickel content for capacity, while the surface coating provides improved mass transfer properties. The metal oxide coating layer creates optimized pathways for ion and electron transport, addressing the mass transfer issue locally at the surface without compromising the high-capacity bulk material
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method results in a high-nickel ternary cathode material with uniform primary particle size, tight particle combination, and ionic conductor coatings that improve electrical conductivity, capacity, cycle, and rate performances.
Implementation Method 1
performing primary sintering in an oxygen atmosphere to obtain a primary-sintered material
Implementation Method 2
mixing a LiOH powder with a high-nickel ternary precursor according to a molar ratio of (0.6 to 0.95)：1，and performing primary sintering
Implementation Method 3
adding a metal oxide into a LiOH solution to obtain a mixed solution
Implementation Method 4
adding a metal oxide into a LiOH solution to obtain a mixed solution, wherein the metal oxide is at least one of oxides of Mo, W or Sn; and the mixed solution is a mixed solution of Li2MoO4, Li2WO4 or Li2SnO3 with LiOH
Implementation Method 5
drying and crushing the mixed material to obtain a power material
Implementation Method 6
spraying an atomized boric acid alcohol solution onto the secondary-sintered material, and then tempering to obtain the high-nickel ternary cathode material
Implementation Method 7
spraying an atomized boric acid alcohol solution onto the secondary-sintered material, and then tempering
Data Source
AI summary
Disclosed is a preparation method for a high-nickel ternary cathode material, including the steps of mixing a LiOH powder with a high-nickel ternary precursor according to a molar ratio of (0.6 to 0.95):1, performing primary sintering in an oxygen atmosphere, adding a metal oxide into a LiOH solution to obtain a mixed solution, mixing the mixed solution with a primary-sintered material in a protective atmosphere, drying and crushing a mixed material, performing secondary sintering on a powder material, spraying an atomized boric acid alcohol solution onto a secondary-sintered material, and then tempering to obtain the high-nickel ternary cathode material.