Nickel Cathode Material with Bimodal Particle Size for Battery Stability
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Solution Overview
Problem
Current nickel-based cathode active materials in lithium batteries suffer from poor lifetime characteristics and unsatisfactory thermal stability due to side reactions caused by residual surface lithium and cation mixing, leading to reduced energy density and capacity.
Innovation Solution
A cathode active material with a specific structure comprising secondary particles made of nickel-containing lithium transition metal oxides, featuring a layered crystal structure, a large specific area, and a uniform particle size distribution, is developed. This material includes primary particles of varying sizes and porosity, optimized through a method involving a vertical plate network-structured precursor and controlled thermal treatments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a nickel-based cathode active material with high capacity is used, then the energy density is improved, but the lifetime characteristics and thermal stability deteriorate due to side reactions from residual surface lithium and cation mixing
Solution Approach 1:
The patent applies preliminary action by conducting a first thermal treatment at a high temperature (900°C to 1100°C) before the second thermal treatment. This preliminary high-temperature treatment removes residual surface lithium and prevents cation mixing in advance, thereby eliminating the root causes of side reactions before they can deteriorate lifetime characteristics and thermal stability during battery operation
Solution Approach 2:
The patent utilizes parameter changes by implementing a two-stage thermal treatment process with different temperature parameters. The first treatment uses a higher temperature (900°C to 1100°C) specifically targeted at removing residual lithium and preventing cation mixing, while the second treatment uses a lower temperature (700°C to 900°C) for final material formation. This parameter optimization resolves the contradiction by achieving high capacity materials without the detrimental side reactions
2Use of energy by moving object
If a nickel-based cathode active material with high capacity is used, then the energy density is improved, but the thermal stability deteriorates due to side reactions from residual surface lithium and cation mixing
Solution Approach 1:
The patent applies preliminary action by conducting a first thermal treatment at a high temperature (900°C to 1100°C) before the second thermal treatment. This preliminary high-temperature treatment removes residual surface lithium and prevents cation mixing in advance, thereby eliminating the root causes of side reactions before they can deteriorate lifetime characteristics and thermal stability during battery operation
Solution Approach 2:
The patent utilizes parameter changes by implementing a two-stage thermal treatment process with different temperature parameters. The first treatment uses a higher temperature (900°C to 1100°C) specifically targeted at removing residual lithium and preventing cation mixing, while the second treatment uses a lower temperature (700°C to 900°C) for final material formation. This parameter optimization resolves the contradiction by achieving high capacity materials without the detrimental side reactions
3Productivity
If the cathode active material precursor has a large specific area and large average particle diameter, then the manufacturing efficiency is improved, but the particle size uniformity may deteriorate
Solution Approach 1:
The patent utilizes parameter changes by optimizing both the physical parameters (specific area of 8-25 m²/g, average particle diameter of 13.7 μm or greater) and chemical parameters (controlled thermal treatment temperatures and durations) of the precursor. These parameter optimizations enable the production of precursors with large size and high efficiency while maintaining uniform particle size distribution through precise control of the thermal treatment conditions
Solution Approach 2:
The patent applies local quality by ensuring that the precursor particles, while having large overall dimensions for manufacturing efficiency, possess uniform local characteristics throughout their structure. The vertical plate network structure and controlled porosity (less than or equal to 10%) ensure consistent properties across different regions of each particle, maintaining manufacturing precision even at large scale
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 solution enhances the initial efficiency and capacity of lithium batteries by improving electrode plate density, reducing irreversible lithium intercalation, and enhancing thermal stability, leading to improved cycle characteristics and reduced internal resistance.
Implementation Method 1
first thermally treating the mixture to produce a first product; washing the first product with water to produce a washed product; drying the washed product to produce a dried product; and second thermally treating the dried product to prepare the cathode active material
Data Source
AI summary
A cathode active material includes a secondary particle including an aggregate of a plurality of primary particles, wherein the secondary particle includes a nickel-containing lithium transition metal oxide having a layered crystal structure, wherein the plurality of primary particles includes a first primary particle having a size greater than about 400 nanometers, a second primary particle having a size less than about 150 nanometers, and a third primary particle having a size of about 150 nanometers to about 400 nanometers, wherein the third primary particle has a area of greater than or equal to about 80% of a total area of the plurality of primary particles, and wherein the secondary particle has a porosity of less than or equal to about 10% of a total area of the cathode active material.