Tungsten-Coated Cathode Material for Stable High-Capacity Li Batteries
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium secondary batteries face challenges in achieving extended life-span and higher capacity while maintaining chemical and mechanical stability, as high-capacity cathode active materials can lead to chemical instability and gas generation due to side reactions with the electrolyte.
Innovation Solution
A cathode active material for lithium secondary batteries is developed, comprising lithium-nickel metal oxide particles with a tungsten-containing coating, where the tungsten content is optimized between 100 ppm to 5,000 ppm and carbon content is controlled at 500 ppm or less, forming a barrier against side reactions and enhancing high-temperature stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-capacity cathode active material is used, then capacity is improved, but chemical stability and mechanical stability deteriorate
Solution Approach 1:
The patent applies composite materials by forming a tungsten-containing coating on the surface of lithium-nickel metal oxide particles. This coating layer creates a composite structure where the core provides high capacity while the coating provides chemical stability, resolving the contradiction between capacity and stability.
Solution Approach 2:
The patent changes the chemical composition parameters by controlling tungsten content at 100-5,000 ppm and carbon content at 500 ppm or less. This parameter optimization allows the material to achieve both high capacity and improved chemical stability through precise compositional control.
2Quantity of substance
If high-capacity cathode active material is used, then capacity is improved, but life-span properties deteriorate
Solution Approach 1:
The tungsten-containing coating creates a protective composite structure that maintains chemical stability during cycling, thereby extending the battery's operational life-span while preserving the high-capacity characteristics of the lithium-nickel metal oxide core.
Solution Approach 2:
By optimizing the tungsten content parameter to 100-5,000 ppm, the coating provides sufficient protection against degradation without excessive thickness that would impede lithium ion diffusion, thus extending life-span while maintaining high capacity.
3Quantity of substance
If high-capacity cathode active material is used, then capacity is improved, but gas generation increases
Solution Approach 1:
The tungsten-containing coating acts as an intermediary layer between the high-capacity lithium-nickel metal oxide and the electrolyte, preventing direct contact and side reactions that would generate gas, thus eliminating the harmful effect while preserving capacity.
Solution Approach 2:
The patent converts the potential harm of surface impurities and unreacted residues into a benefit by using tungsten-containing compounds as a protective coating. This coating transforms the surface into a stable barrier that prevents harmful side reactions with the electrolyte.
4Quantity of substance
If high-capacity cathode active material is used, then capacity is improved, but operational stability deteriorates
Solution Approach 1:
The composite structure with tungsten-containing coating provides a stable interface that maintains operational reliability during cycling, preventing the degradation mechanisms that would otherwise compromise the high-capacity material's performance consistency.
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 tungsten-containing coating improves resistance properties, capacity stability, and chemical stability, preventing gas generation and explosion, thereby extending the life-span and enhancing the high-temperature performance of lithium secondary batteries.
Implementation Method 1
a tungsten-containing coating formed on at least a portion of the active material particles... preventing gas generation and explosion due to side reactions with the electrolyte
Implementation Method 2
generation of carbon dioxide by a carbon component included in the residues may be reduced through the tungsten-containing coating
Data Source
AI summary
A cathode active material for a lithium secondary battery according to an embodiment of the present invention includes active material particles containing a lithium-nickel metal oxide, and a tungsten-containing coating formed on at least portion of the active material particles. A content of tungsten measured by an ICP (inductively coupled plasma) is in a range from 100 ppm to 5,000 ppm, and a content of carbon measured by a CS (Carbon-Sulfur) analyzer is 500 ppm or less.