Lithiated Silicon Oxide Anode Coating for Stable Battery Slurry
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Solution Overview
Problem
The use of silicon oxide materials as anode materials in lithium-ion batteries faces challenges due to their low initial coulombic efficiency and strong hydrophilicity, which leads to instability and poor processability of the slurry during manufacturing.
Innovation Solution
The development of a lithiated silicon-oxygen anode material with a core and a coating layer, where the mass ratio of lithium to oxygen satisfies 0.4>a>b, and the coating layer is formed using a polycarboxylic acid carbon source to improve hydrophobicity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pre-lithiation treatment is performed on silicon oxide material to improve electrochemical performance, then initial coulombic efficiency is improved, but surface hydrophilicity increases causing slurry instability
Solution Approach 1:
A coating layer with thickness of 1 nm to 1000 nm is formed on the surface of the pre-lithiated silicon oxide material. This thin film acts as a barrier that reduces surface hydrophilicity and prevents aqueous solvent infiltration, thereby maintaining slurry stability while preserving the electrochemical benefits of pre-lithiation.
Solution Approach 2:
The anode material is designed as a composite structure combining pre-lithiated silicon oxide core with a coating layer. This composite approach allows the inner core to provide high capacity through lithium insertion/extraction while the outer coating provides hydrophobicity and structural stability, resolving the contradiction between electrochemical performance and slurry stability.
2Reliability
If pre-lithiation treatment is performed to increase lithium content, then electrochemical performance is improved, but material hydrophilicity increases causing equipment corrosion
Solution Approach 1:
The coating layer forms a protective barrier that isolates the highly hydrophilic pre-lithiated material from contact with aqueous environment in slurry preparation. This prevents the material from corroding equipment while maintaining its electrochemical functionality during battery operation.
Solution Approach 2:
The coating layer acts as an intermediary between the pre-lithiated silicon oxide material and the external environment. It mediates the interaction by providing a hydrophobic interface that prevents direct contact between water-containing slurry and the reactive lithium-containing compounds, thereby eliminating equipment corrosion.
3Ease of manufacture
If coating layer is added to reduce surface lithium exposure, then slurry processability is improved, but manufacturing complexity increases
Solution Approach 1:
The coating layer is applied in advance during the material synthesis process, before the material enters slurry preparation. This preliminary action ensures that the material possesses the required hydrophobicity from the outset, preventing slurry instability issues without requiring additional process steps during manufacturing.
Solution Approach 2:
The coating formation process is merged with the existing material synthesis and pre-lithiation processes. By combining these steps into a unified manufacturing flow, the patent avoids adding separate coating equipment and process lines, thereby improving slurry processability without significantly increasing manufacturing complexity.
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 proposed solution enhances the electrochemical performance and processability of the anode material, reducing the exposure of lithium-containing compounds and minimizing the infiltration of water solvent, thereby improving the stability and efficiency of the lithium-ion battery.
Implementation Method 1
the surface of the material has abundant lithium-containing compounds such as Li2SiO3, LiOH, Li2CO3, etc., thereby presenting extremely strong hydrophilicity... the coating layer... improve hydrophobicity
Implementation Method 2
the coating layer is formed using a polycarboxylic acid carbon source
Data Source
AI summary
The present disclosure discloses an anode material and a preparation method and application thereof, the anode material includes a core and a coating layer located on at least part of the surface of the core, the core includes a silicon oxide material, the anode material contains a lithium element, and a mass ratio of the lithium element to the oxygen element in the anode material is a; the anode material is tested through an X-ray photoelectron spectroscopy (Thermo Scientific K-Alpha), a mass ratio of the lithium element to the oxygen element in the region corresponding to the information detectable in the detection process from the surface of the anode material to the inner center region of the anode material is b, a relationship between a and b satisfies 0.4>a>b, the ratio of the lithium element to the oxygen element on the surface layer of the anode material is controlled to be smaller than the ratio of the overall lithium element to the oxygen element of the material, so that the lithium element is more present in the inner center region of the material, the corrosion effect of a water solvent on Si crystal grains in the inner center region of the silicon oxide material is weakened by reducing the content of the lithium element on the surface, and the slurry processing stability is improved.