Cathode Precursor Spray Drying for Higher Density and Lower Chloride
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Solution Overview
Problem
Existing methods for preparing Li-containing cathode active materials, such as spray pyrolysis from chloride or nitrate solutions, result in high Cl content or the production of polluting gases like NO and NO2, and have low furnace capacity due to low density of the precursor materials.
Innovation Solution
A method involving spray pyrolysis and subsequent spray drying of an aqueous slurry to produce a mixed metal oxide precursor with increased bulk density, using soluble chlorides and including washing and size reduction steps to enhance homogeneity and reduce residual anions, resulting in a precursor with improved furnace capacity and reduced pollution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If spray pyrolysis from mixed chloride solution is used to prepare mixed Ni-Co-Mn oxide, then the precursor can be produced, but the final Li-containing cathode active material contains high Cl content and the furnace capacity is low due to low density
Solution Approach 1:
The patent extracts and removes chloride ions from the precursor material through washing with water or dilute acid solutions before the lithium reaction step. This extraction process eliminates the harmful Cl content that would otherwise contaminate the final cathode active material, while preserving the beneficial mixed metal oxide structure.
Solution Approach 2:
The patent performs preliminary washing and drying steps on the spray-dried precursor to remove residual chlorides before the lithium reaction. This preliminary action prevents chloride contamination in the final product and improves the quality of the cathode active material without affecting the core synthesis process.
2Ease of manufacture
If spray pyrolysis from mixed chloride solution is used to prepare mixed Ni-Co-Mn oxide, then the precursor can be produced, but the furnace capacity for subsequent reaction with Li-source is low due to low density
Solution Approach 1:
The patent changes the physical parameters of the precursor by controlling the spray drying process to produce particles with optimized density and morphology. By adjusting drying conditions, the precursor achieves higher bulk density while maintaining its chemical composition, thereby increasing furnace capacity for the subsequent lithium reaction.
3Productivity
If spray pyrolysis from mixed nitrate solution including Li is used followed by spray drying, then LiMn2O4 can be produced, but gaseous NO and NO2 are released which are highly polluting
Solution Approach 1:
The patent converts the harmful nitrate decomposition pathway into a beneficial chloride-based pathway. By using chloride salts as precursors and removing chlorides through washing, the process avoids the formation of polluting NO and NO2 gases entirely, while still achieving efficient production of Li-containing cathode materials.
Solution Approach 2:
The patent changes the chemical composition parameters by substituting nitrate salts with chloride salts in the precursor solution. This parameter change fundamentally alters the decomposition pathway during pyrolysis, eliminating the formation of nitrogen oxide pollutants while maintaining the effectiveness of the synthesis process.
4Productivity
If spray pyrolysis from mixed chloride solution including Li followed by spray drying is used, then lithiated metal oxide can be produced, but high Cl content in final product makes it less suitable for batteries
Solution Approach 1:
The patent extracts chloride ions from the precursor through washing with water or dilute acid solutions before the lithium reaction step. This extraction process eliminates the harmful Cl content that would otherwise contaminate the final cathode active material, while preserving the beneficial lithiated metal oxide structure and maintaining high productivity.
Solution Approach 2:
The patent performs preliminary washing and drying steps on the spray-dried precursor to remove residual chlorides before the lithium reaction. This preliminary action prevents chloride contamination in the final product, ensuring high battery suitability while maintaining efficient production of lithiated metal oxide.
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 increases the bulk density of the precursor material, enhancing the furnace capacity for lithium reaction and reducing pollutant gases, while maintaining cost-effectiveness and improving the quality of the final Li-containing cathode active material.
Implementation Method 1
a spray pyrolysis step in which a metal oxide is produced by decomposition in a heated chamber of droplets of an aqueous solution
Implementation Method 2
a spray drying step in which an aqueous slurry comprising said metal oxide, either directly from the spray pyrolysis step or after one or more intermediate processing steps, is spray dried to form said precursor material
Data Source
AI summary
Method for preparing a precursor material for a Li-containing cathode active material for a battery, wherein the method comprises a spray pyrolysis step in which a metal oxide is produced by decomposition in a heated chamber of droplets of an aqueous solution, wherein either the metal oxide is a mixed metal oxide comprising the element Ni and one or both of the elements Co and Mn and the aqueous solution is a mixed solution of salts of Ni and of Co and/or Mn or the metal oxide is a Ni oxide and the aqueous solution is a solution of a salt of Ni, characterised in that the method comprises a spray drying step in which an aqueous slurry comprising said metal oxide is spray dried to form said precursor material.