Cathode Active Material Coating for Lithium Salt Residue Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium secondary batteries face issues with non-uniform chemical structures due to lithium precipitation, leading to degraded life-span and capacity retention, and existing washing methods fail to sufficiently remove lithium salt impurities, causing surface damage to cathode active materials.
Innovation Solution
A cathode active material for lithium secondary batteries is developed, comprising lithium metal oxide particles coated with an organic poly-phosphate or organic poly-phosphonate, which forms a protective layer on the surface, enhancing structural stability and removing impurities effectively.
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 parameters of the washing solution from water to an organic solvent system containing phosphoric acid and chelating agents. This parameter change enables effective removal of lithium salt impurities while preventing surface damage to the cathode active material particles, as the organic solvent system provides controlled chemical interaction that avoids the harmful effects of aqueous washing.
Solution Approach 2:
The patent employs a composite washing solution comprising phosphoric acid and chelating agents (such as EDTA or NTA) in an organic solvent matrix. This composite formulation works synergistically: phosphoric acid removes surface lithium salts, chelating agents complex with metal ions to prevent reprecipitation, and the organic solvent provides a non-aqueous environment that protects the material surface while enabling effective impurity removal.
2Quantity of substance
If conventional washing methods are used, then processing is simple, but impurities are not sufficiently removed and surface damages occur
Solution Approach 1:
The patent modifies the chemical composition parameters of the washing solution to include phosphoric acid concentration (0.1-10 wt%), chelating agent concentration (0.1-5 wt%), and organic solvent type. These parameter changes create a washing system that achieves superior impurity removal while maintaining practical process simplicity, as the treatment can still be performed using standard washing equipment and procedures.
3Quantity of substance
If lithium metal oxide is used as cathode active material, then high capacity is achieved, but non-uniformity of chemical structure due to lithium precipitation occurs and life-span is degraded
Solution Approach 1:
The patent adjusts the chemical composition parameters of the washing solution, specifically phosphoric acid concentration (0.1-10 wt%) and chelating agent concentration (0.1-5 wt%), to control the chemical interaction with lithium metal oxide surfaces. This removes lithium salt impurities and prevents non-uniform chemical structure formation, thereby maintaining high lithium content while improving operational stability and life-span.
Solution Approach 2:
The patent uses a composite washing solution containing phosphoric acid and chelating agents that work together to treat lithium metal oxide surfaces. Phosphoric acid removes surface lithium salts through chemical reaction, while chelating agents bind metal ions to prevent reprecipitation and ensure uniform chemical structure. This composite approach maintains high lithium content while significantly improving operational stability and preventing life-span degradation.
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 organic coating improves operational stability and electrical properties, resulting in improved capacity retention and reduced impurities, thereby extending the battery's life-span and maintaining high capacity.
Implementation Method 1
an organic poly-phosphate or an organic poly-phosphonate formed on at least portion of a surface of the lithium metal oxide particle
Implementation Method 2
a method of preparing a cathode active material for a lithium secondary battery includes cleaning the lithium metal oxide particle using a washing solution that includes an organic poly-phosphate compound or an organic poly-phosphonate compound
Data Source
AI summary
A cathode active material for a lithium secondary battery includes a lithium metal oxide particle, and an organic poly-phosphate or an organic poly-phosphonate formed on at least portion of a surface of the lithium metal oxide particle. Chemical stability of the lithium metal oxide particle may be improved and surface residues may be reduced by the organic poly-phosphate or the organic poly-phosphonate.