Tungsten Surface Treatment of Li-Ion Cathode Material for Simpler Production
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Solution Overview
Problem
Existing methods for manufacturing lithium-ion secondary battery positive electrode active materials are costly and inefficient, particularly when scaled up for mass production, due to the need for multiple steps and the use of specialized equipment like aluminum bags and vacuum dryers.
Innovation Solution
A method involving a mixing step where lithium-nickel composite oxide is mixed with a tungsten compound powder while being heated, followed by a heat treatment step to evaporate water and fix the tungsten and lithium-containing compounds on the surface of the lithium-nickel composite oxide particles, without the need for sealing in an aluminum container.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple manufacturing steps and specialized equipment (aluminum bags, vacuum dryers) are used, then manufacturing precision and reliability are improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines multiple manufacturing steps (mixing, drying, and heat treatment) into a single integrated firing process. The slurry is applied directly to the green body and fired in one step, eliminating the need for separate drying and heat treatment steps, thereby reducing device complexity while maintaining manufacturing precision
Solution Approach 2:
The firing process serves multiple functions simultaneously: it acts as a drying step to remove solvent, a bonding step to attach the positive electrode active material to the green body, and a sintering step to form the final electrode structure. This multi-functionality reduces the number of specialized equipment needed
2Manufacturing precision
If multiple manufacturing steps and specialized equipment are used, then manufacturing precision is improved, but productivity decreases
Solution Approach 1:
The patent merges multiple sequential steps (slurry application, drying, and heat treatment) into a single firing operation. This integration eliminates intermediate handling and transfer operations, significantly improving productivity while maintaining the quality outcomes of each individual step
Solution Approach 2:
The firing process continuously performs multiple functions in sequence within a single operational cycle: the slurry is applied and then immediately fired, which simultaneously dries the solvent, bonds the material, and sinteres the electrode. This continuous process eliminates idle time between steps and improves overall productivity
3Manufacturing precision
If spray-drying and multiple processing steps are used, then manufacturing precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent extracts and eliminates unnecessary intermediate steps (separate spray-drying, drying, and heat treatment steps) from the manufacturing process. By keeping only the essential firing step that accomplishes multiple objectives, the process becomes simpler and less costly while maintaining precision
Solution Approach 2:
The invention uses a simple slurry application method that does not require expensive specialized equipment like spray-dryers. The process uses basic, readily available materials and equipment, making manufacturing more accessible and cost-effective
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
This method allows for the inexpensive production of positive electrode active materials with high capacity and output when used in lithium-ion secondary batteries, while also improving cycle characteristics and reducing positive electrode resistance.
Implementation Method 1
a heat treatment step of heat-treating the tungsten mixture, wherein the water content, which is a proportion of the water in the starting material and the lithium-nickel composite oxide, is 3.0% by mass or more
Implementation Method 2
a mixing step of mixing a lithium-nickel composite oxide which is a starting material with a tungsten compound powder without lithium, while being heated, to prepare a tungsten mixture
Data Source
AI summary
A method of manufacturing a positive electrode active material for a lithium ion secondary battery includes a mixing step of mixing a lithium-nickel composite oxide which is a starting material with a tungsten compound powder without lithium, while being heated, to prepare a tungsten mixture, and a heat treatment step of heat-treating the tungsten mixture. The lithium-nickel composite oxide contains lithium (Li), nickel (Ni), and an element M (M), wherein, the element M is at least one element selected from Mn, V, Mg, Mo, Nb, Ti, Co, and Al, wherein, in the starting material, a ratio of number of tungsten atoms to a total number of nickel atom and the element M atoms contained in the lithium-nickel composite oxide is 0.05 at. % or more and 3.00 at. % or less.