Lithium-Nickel Cathode Processing With Tungsten Surface Treatment
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Solution Overview
Problem
Current methods for manufacturing lithium-ion secondary battery positive electrode active materials are costly and inefficient, leading to reduced battery capacity and output due to the replacement of heterogenous elements like Mo, W, Nb, and Re with Ni, and the need for multiple processing steps increases costs further.
Innovation Solution
A method involving a water-washing step to form a washed cake of lithium-nickel composite oxide, followed by a mixing step with a tungsten compound, and a heat treatment step to achieve a specific tungsten-to-nickel ratio, allowing for the formation of lithium tungstate on the surface of the composite oxide particles, thereby enhancing capacity and output while reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If heterogenous elements (Mo, W, Nb, Re) are added to lithium-nickel composite oxide to reduce resistance and improve output, then battery output and charge-discharge characteristics are improved, but manufacturing cost increases
Solution Approach 1:
The patent changes the chemical composition parameters by introducing tungsten (W) at specific concentrations (0.01-5 atom%) in the lithium-nickel composite oxide formula. This parameter optimization achieves low resistance and high output characteristics while controlling manufacturing costs through precise compositional control rather than using expensive alternative materials.
Solution Approach 2:
The patent creates a composite material system by combining lithium-nickel composite oxide with tungsten compounds (such as tungsten oxide or tungsten carbide). This composite approach leverages the beneficial properties of tungsten (high melting point, electrical conductivity, catalytic activity) to enhance battery output while maintaining cost-effectiveness through controlled incorporation rather than full substitution with expensive materials.
2Manufacturing precision
If multiple processing steps (pulverizing, spray-drying, firing) are used to manufacture positive electrode active material, then manufacturing precision and material uniformity are improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent merges multiple processing operations into integrated steps. Specifically, the mixing of lithium-nickel composite oxide with tungsten compounds is combined with the granulation process, and the drying and firing steps are optimized as a continuous sequence. This integration reduces the number of separate equipment units and operational interruptions while maintaining material uniformity through controlled processing parameters.
Solution Approach 2:
The patent implements continuous processing where the positive electrode active material is continuously mixed, granulated, dried, and fired in a streamlined sequence without interruption. This continuous action ensures uniform material properties throughout production while reducing manufacturing complexity by eliminating batch-to-batch transitions and intermediate handling steps.
3Power
If tungsten compound is added to improve capacity and output, then battery performance is enhanced, but reaction resistance may increase due to improper dispersion
Solution Approach 1:
The patent applies local quality by ensuring tungsten compounds are uniformly dispersed at the microscopic level within the lithium-nickel composite oxide matrix. Through controlled mixing and granulation processes, tungsten is distributed evenly throughout the material structure, creating local regions with optimized electrochemical properties. This uniform local distribution prevents aggregation that would cause high reaction resistance while maintaining enhanced capacity and output characteristics.
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 enables the production of positive electrode active materials with high capacity and output at a lower cost, improving charge-discharge characteristics and reducing reaction resistance, thus enhancing the overall performance of lithium-ion secondary batteries.
Implementation Method 1
a heat treatment step of heat-treating the tungsten mixture
Implementation Method 2
formation of lithium tungstate on the surface of the composite oxide particles
Implementation Method 3
a water-washing step includes a lithium-nickel composite oxide containing lithium (Li), nickel (Ni), and an element M (M) being washed with water
Implementation Method 4
a mixing step of mixing, while heating, the washed cake and a tungsten compound without lithium to obtain a tungsten mixture
Data Source
AI summary
A method of manufacturing a positive electrode active material for a lithium-ion secondary battery includes a water-washing step of washing a lithium-nickel composite oxide containing Li, Ni, and an element M with water, and conducting a filtration to form a washed-cake, a mixing step of mixing, while heating, the washed-cake and a tungsten compound without lithium while heating to obtain a tungsten mixture, and a heat treatment step of heat-treating the tungsten mixture, wherein a water content of the washed-cake is 3.0% by mass or more and 10.0% by mass or less, a ratio of a number of tungsten atoms contained in the tungsten mixture to a total number of nickel and the element M atoms contained in the lithium-nickel composite oxide is 0.05 at. % or more and 3.00 at. % or less, and a temperature of the mixing step is 30° C. or higher and 70° C. or lower.