SiOx-Li2Si2O5 Anode Material for Stable Prelithiated Slurry Processing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing lithium-ion batteries face challenges with high theoretical capacity silicon-based anode materials like SiOx due to irreversible lithium consumption during SEI film formation, leading to poor processing performance and low initial efficiency, exacerbated by the water solubility of phases like Li2SiO3, Li4SiO4, and Li2O, which cause gas production, low viscosity, and pinholes during coating.
Innovation Solution
The anode material comprises SiOx dispersed in Li2Si2O5, with a pH of 7 < pH < 10.7, and optionally coated with a carbon layer, prepared through a method involving mixing silicon oxide with a reducing lithium compound and a nucleating conversion agent or heat absorbent to transform Li2SiO3 into Li2Si2O5, ensuring stability and eliminating the need for additional surface treatments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods (stirring, spraying, dip-coating) are used to form the negative electrode, then the electrode can be manufactured, but fine particles detach during charging/discharging causing performance degradation and short circuits
Solution Approach 1:
The patent applies a thin film coating method where a slurry containing fine particles is coated onto the negative electrode surface and dried to form a thin film layer. This thin film structure effectively binds fine particles to the electrode surface, preventing their detachment during charging and discharging cycles, thus resolving the reliability issue without requiring conventional stirring or spraying methods.
Solution Approach 2:
The patent introduces a binder as an intermediary substance in the slurry that mediates between the fine particles and the negative electrode. The binder adheres to both the fine particles and the electrode surface, creating a stable connection that prevents particle detachment. This intermediary approach eliminates the harmful effects of loose fine particles while maintaining electrode performance.
2Quantity of substance
If fine particles are used in the negative electrode to improve capacity, then energy density increases, but particle detachment causes safety issues and performance degradation
Solution Approach 1:
The thin film coating technique forms a stable layer on the negative electrode that securely holds fine particles in place. This allows the electrode to utilize the high capacity of fine particles while preventing their detachment, thereby maintaining both high lithium ion capacity and electrode safety during cycling operations.
Solution Approach 2:
The patent changes the physical state and distribution parameters of fine particles by converting them from loose, detached particles into a structured thin film layer on the electrode surface. This parameter change transforms the harmful loose particles into a stable, integrated structure that maintains safety while preserving the high capacity benefits of fine particles.
3Manufacturing precision
If a slurry coating method is used to form the negative electrode, then fine particles can be effectively utilized, but the coating process complexity increases
Solution Approach 1:
The slurry coating method allows the coating process to be self-regulating, where the slurry naturally forms a uniform thin film on the electrode surface through controlled drying. This self-service approach achieves uniform particle distribution without requiring complex coating equipment or multi-step processes, thereby maintaining manufacturing precision while minimizing process 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
This approach stabilizes processing, enhances initial efficiency, and extends cycle life by preventing capacity reduction and initial efficiency loss, while simplifying the preparation process and avoiding gas production and pinholes.
Implementation Method 1
a diaphragm, which moves toward the negative electrode when the negative electrode potential is lowered
Data Source
Figure 1~3b
Figure 4~5b
AI summary
This application provides an anode material, a preparation method thereof and a lithium ion battery. The anode material comprises SiOx and Li2Si2O5, wherein SiOx is dispersed in Li2Si2O5, and wherein 0≤x≤1.2. The preparation method comprises the following steps of: mixing a silicon oxide SiOy, a reducing lithium-containing compound and an auxiliary agent, and performing heat treatment to obtain the anode material, wherein the auxiliary agent comprises a nucleating conversion agent or a heat absorbent, and 0<y<2. The preparation method provided by this application, by using a nucleating conversion agent or a heat absorbent, can make the lithium silicate in the prepared product is only Li2Si2O5 without other lithium silicate phases, and because Li2Si2O5 is insoluble in water, the processing stability problems of the pre-lithiated material, such as gas production of slurry, low viscosity, tailing during coating, pinholes and pores after drying the polar plate, are solved.