Thio-Coated Cathode Active Material for Lithium Salt Residue Control
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Solution Overview
Problem
Lithium secondary batteries face challenges with non-uniform chemical structures in lithium metal oxide cathode active materials, leading to reduced lifespan and capacity due to lithium precipitation and structural damage during charging and discharging, and existing washing methods fail to adequately remove lithium salt impurities, causing surface damage.
Innovation Solution
A cathode active material is developed with a thio-based compound, such as thioamide, tri-thiocarbonate, or thiosulfate, coated on lithium metal oxide particles to enhance structural stability and prevent side reactions, using a washing process that includes a thiosulfate compound to remove impurities while forming a protective thio-coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If water washing is used to remove lithium salt impurities, then impurity removal is attempted, but surface damages of cathode active material particles are caused and impurities are not sufficiently removed
Solution Approach 1:
The patent changes the chemical composition parameter of the washing solution by adding a thio-based compound to water, transforming it from a simple aqueous solution to a chemically enhanced solution that can remove impurities without causing surface damage. The thio-based compound concentration is controlled at 0.01-5 wt% to achieve optimal cleaning效果.
Solution Approach 2:
The thio-based compound acts as an intermediary substance between the water washing solution and the cathode active material surface. It mediates the cleaning process by forming a protective complex with lithium salt impurities, enabling their removal without direct harsh interaction between water and the material surface.
2Ease of manufacture
If conventional washing methods are used, then processing simplicity is maintained, but lithium salt impurities are not sufficiently removed
Solution Approach 1:
The patent modifies the chemical parameters of the washing solution by introducing a thio-based compound, which enhances impurity removal capability while maintaining the overall simplicity of the washing process. The enhanced solution can be applied using conventional washing equipment and procedures.
3Use of energy by moving object
If lithium metal oxide is used as cathode active material, then high operational voltage and energy density are achieved, but non-uniformity of chemical structure due to lithium precipitation occurs reducing lifespan and capacity
Solution Approach 1:
The patent applies preliminary action by performing surface treatment with thio-based compound before the lithium metal oxide is assembled into the battery. This pre-treatment establishes a protective layer that prevents lithium precipitation and maintains chemical structure uniformity during subsequent charging and discharging cycles.
Solution Approach 2:
The thio-based compound forms an intermediary protective layer on the lithium metal oxide surface. This intermediate layer acts as a barrier that prevents direct contact between the lithium metal oxide and the electrolyte, thereby preventing lithium precipitation while allowing ion transport.
4Productivity
If lithium metal oxide structure is subjected to repeated charging and discharging, then battery operation is enabled, but structure transformation or damage occurs degrading life-span stability and capacity retention
Solution Approach 1:
The patent applies beforehand cushioning by pre-coating the lithium metal oxide surface with a thio-based compound before battery assembly. This protective coating acts as a cushioning layer that absorbs and distributes mechanical stress during repeated charging and discharging, preventing structural transformation or damage.
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 thio-coating improves operational stability and electrical properties by preventing structural damage and effectively removing lithium salt impurities, resulting in enhanced capacity retention and lifespan of lithium secondary batteries.
Implementation Method 1
a thio-based compound formed on at least portion of a surface of the lithium metal oxide particle
Implementation Method 2
a washing process that includes a thiosulfate compound to remove impurities
Data Source
AI summary
A cathode active material for a lithium secondary battery includes a lithium metal oxide particle and a thio-based compound formed on at least portion of a surface of the lithium metal oxide particle. The thio-based compound has a double bond that contains a sulfur atom. Chemical stability of the lithium metal oxide particle may be improved and surface residues may be reduced by the thio-based compound.