Complex Oxide Electrode Surface Modification for Lithium Battery Stability
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Solution Overview
Problem
Lithium battery electrodes made from complex oxides can cause electrolyte degradation due to surface OH groups, leading to reduced performance and cyclability, and existing solutions for creating a physical barrier are complex, expensive, or inefficient.
Innovation Solution
Surface-modifying complex oxide particles with organic phosphorus groups fixed by covalent bonds, achieving a coverage rate of 40-60%, which reduces electrolyte degradation and improves cyclability without the need for a continuous physical barrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a continuous physical barrier coating is applied to the complex oxide surface, then electrolyte degradation is prevented, but manufacturing complexity and cost increase significantly
Solution Approach 1:
The patent applies local quality by modifying only the surface of the complex oxide particles with phosphorus-containing compounds, rather than creating a continuous coating throughout. The surface treatment introduces P-O-Li bonds specifically at the particle surfaces where electrolyte contact occurs, providing localized protection against electrolyte degradation without requiring a complete physical barrier structure.
Solution Approach 2:
The patent changes the chemical parameters of the oxide surface by introducing phosphorus-containing groups that form P-O-Li bonds. This chemical modification alters the surface properties to be less reactive toward the electrolyte, preventing degradation through chemical stabilization rather than physical isolation. The treatment modifies surface composition and bonding characteristics to achieve electrolyte compatibility.
2Reliability
If a thick coating layer is applied to ensure continuous barrier, then electrolyte protection improves, but ionic and electronic conductivity decrease
Solution Approach 1:
The patent employs an ultra-thin surface treatment layer formed by phosphorus-containing compounds on the oxide particles. This thin film approach provides sufficient electrolyte protection while maintaining the underlying oxide's conductive properties. The treatment forms a molecular-level surface modification rather than a thick coating, ensuring that ionic and electronic transport pathways remain open.
Solution Approach 2:
The protective function is localized to the particle surfaces where electrolyte contact occurs, while the bulk material retains its original conductive properties. The phosphorus treatment creates a thin protective interface layer without forming a continuous thick barrier that would block ion and electron transport throughout the entire material structure.
3Productivity
If complex oxide particles with surface OH groups are used, then electrochemical activity is maintained, but electrolyte degradation occurs reducing cyclability
Solution Approach 1:
The patent changes the surface chemical parameters by introducing phosphorus-containing groups that replace or modify the surface OH groups. This creates P-O-Li bonds at the surface, fundamentally altering the chemical reactivity toward the electrolyte. The modification maintains electrochemical activity through Li ion insertion/extraction while preventing the harmful reactions that would otherwise occur with OH groups.
Solution Approach 2:
The patent converts the harmful surface OH groups into beneficial P-O-Li bonded structures. The phosphorus treatment transforms the reactive, electrolyte-degrading surface into a stable, protective interface. The modified surface now provides both electrochemical functionality and electrolyte stability, turning the originally harmful surface chemistry into a protective feature that enhances cyclability.
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 modification significantly reduces electrolyte degradation and enhances the cyclability of lithium batteries, maintaining performance across multiple cycles without the complexity and cost of traditional barrier methods.
Implementation Method 1
particles of a complex oxide which carry on their surface organic phosphorus groups fixed by covalent bond
Data Source
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AI summary
The subject of the invention is an electrode comprising an electrically conducting support carrying an electrode material, which comprises an active substance consisting of particles of a complex oxide which at their surface carry organic phosphorous groups fixed by covalent bonding. The complex oxide may be LiV3O8, LiMn2O4, LiCoO2, LiMPO4 with M = Fe, Mn or Co, Li2MSiO4 with M = Fe, Mn or Co, LiFeBO3, Li4Ti5O12, LiMn2O4, LiNi1-y-zMnyCozAltO2 (0 2O5, MnO2, LiFePO4F, Li3V2(PO4)3, and LiVPO4F. The electrode is useful in particular for lithium batteries.