Positive Electrode Active Material for Low-Gas, Stable Cycling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Non-aqueous electrolyte secondary batteries face challenges in achieving good cycle characteristics due to residual alkaline components from unreacted raw materials in lithium nickel-based composite oxides, which can cause slurry thickening and gas generation during charging, and water-washing methods may worsen battery performance.
Innovation Solution
A method involving contacting lithium transition metal composite oxide particles with a sodium ion-containing solution, followed by mixing with a boron compound and heat-treating the mixture at specific temperatures to produce a positive electrode active material with a layered structure, where sodium is present in the particle boundaries and boron is uniformly dispersed, improving cycle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If water-washing is used to reduce residual alkaline component, then gas generation during charging is reduced, but cycle characteristics worsen
Solution Approach 1:
Sodium sulfate is used as an intermediary substance during the washing process. The sodium ions from sodium sulfate replace residual alkaline components on the particle surfaces, while sulfate ions form a protective layer. This intermediary approach removes harmful alkaline residues without directly damaging the electrode material structure, thus maintaining cycle characteristics while reducing gas generation.
Solution Approach 2:
The invention changes the chemical parameters of the washing solution by using sodium sulfate instead of plain water. By controlling the concentration of sodium sulfate solution and the washing conditions, the process optimizes the removal of alkaline components while preserving the electrode material's structural integrity and electrochemical performance.
2Object-generated harmful factors
If water-washing is used to reduce residual alkaline component, then slurry thickening during electrode fabrication is reduced, but cycle characteristics worsen
Solution Approach 1:
Sodium sulfate acts as an intermediary that selectively removes residual alkaline components responsible for slurry thickening. The sodium ions displace alkaline residues on particle surfaces, reducing slurry viscosity issues during electrode fabrication, while the controlled washing process preserves cycle characteristics.
3Reliability
If sodium ion-containing solution is used for washing, then cycle characteristics are improved, but residual sodium must be controlled
Solution Approach 1:
The invention optimizes washing parameters including sodium sulfate concentration, washing time, and temperature to achieve the right balance. By controlling these parameters, sufficient sodium is introduced to improve cycle characteristics while excessive sodium that would harm performance is prevented from remaining in the final product.
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 positive electrode active material with enhanced electrical charge and discharge characteristics and cycle stability, reducing resistance and maintaining capacity over multiple cycles.
Implementation Method 1
contacting first particles that contain a lithium transition metal composite oxide with a solution containing sodium ions to obtain second particles containing the lithium transition metal composite oxide and sodium element
Implementation Method 2
heat-treating the mixture at a temperature in a range of from 100 °C to 450 °C
Implementation Method 3
a compound containing boron is attached on at least a part of the surfaces of the primary particles
Data Source
Figure 1~3
Figure 4
AI summary
A method of producing a positive electrode active material, the method includes: contacting first particles that contain a lithium transition metal composite oxide with a solution containing sodium ions to obtain second particles containing the lithium transition metal composite oxide and sodium element, wherein the lithium transition metal composite oxide has a layered structure and a composition ratio of a number of moles of nickel to a total number of moles of metals other than lithium in a range of from 0.7 to less than 1; mixing the second particles and a boron compound to obtain a mixture; and heat-treating the mixture at a temperature in a range of from 100 °C to 450 °C.