High-Nickel Cathode Phosphate Network for Residual Lithium Control
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Solution Overview
Problem
High-nickel ternary positive electrode material plates in lithium-ion batteries suffer from residual lithium leading to increased side reactions and impedance, and existing treatments with inorganic phosphoric acid are ineffective in forming a continuous protective layer, requiring high-temperature heating.
Innovation Solution
A phytic acid solution is used to treat the positive electrode material plate, forming a three-dimensional network lithium phosphate layer that protects the active material from side reactions and ensures rapid lithium ion transport, improving electrochemical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inorganic phosphoric acid is used to treat the positive electrode material plate, then the electrochemical performance is improved, but the protective layer cannot form a continuous structure and requires high-temperature heating
Solution Approach 1:
The patent changes the chemical parameters of the treatment solution by using organic phosphoric acid instead of inorganic phosphoric acid, and controls the phosphoric acid content within 5-20 wt% to enable continuous protective layer formation at lower temperatures, resolving the contradiction between electrochemical performance improvement and ease of manufacture
Solution Approach 2:
The patent uses a composite treatment system comprising organic phosphoric acid, alcohol, and water in specific proportions, creating a composite chemical environment that enables continuous protective layer formation without requiring high-temperature heating, thus improving both reliability and ease of manufacture
2Reliability
If inorganic phosphoric acid is used to treat the positive electrode material plate, then the electrochemical performance is improved, but high-temperature heating is required
Solution Approach 1:
The patent changes the chemical composition parameters by substituting inorganic phosphoric acid with organic phosphoric acid and adjusting the solvent system, which lowers the reaction temperature requirement while maintaining electrochemical performance improvement
Solution Approach 2:
The patent introduces alcohol as an intermediary solvent that facilitates the action of organic phosphoric acid at lower temperatures, enabling the treatment to proceed without high-temperature heating while still achieving improved electrochemical performance
3Quantity of substance
If high-nickel ternary positive electrode material is used, then the battery capacity is increased, but residual lithium on the surface leads to increased side reactions and impedance
Solution Approach 1:
The patent converts the harmful residual lithium on the surface into a beneficial component by using phosphoric acid treatment to transform it into a protective phosphate layer, which eliminates side reactions and impedance while preserving the high capacity characteristics of high-nickel ternary material
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 treatment with phytic acid effectively inhibits active material dissolution and enhances lithium ion transport, leading to improved cycling performance and stability of lithium-ion batteries without the need for high-temperature processing.
Implementation Method 1
a three-dimensional network lithium phosphate protective layer is formed on a surface of the positive electrode material plate
Implementation Method 2
the three-dimensional network structure can ensure rapid transport of lithium ions on the surface of the electrode plate
Implementation Method 3
a three-dimensional network lithium phosphate protective layer is formed on a surface of the positive electrode material plate, which effectively protects an active material from side reactions with an electrolyte
Data Source
AI summary
A positive electrode material plate includes: an electrode plate substrate and a coating layer arranged on a surface of the electrode plate substrate. The electrode plate substrate includes a compound of formula I: LiNixCoyM1-x-yO2 (formula I), where 0.6≤x<1, 0≤y≤0.2, and M is at least one of Mn, Al, Ti, Zr, Mg, W, and Mo; and the coating layer is a three-dimensional network lithium phosphate layer with a thickness of 12 nm to 13 nm, and a percentage of lithium phosphate is 20% to 30%.