Active Material Coating Densification via Compression Shearing
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Solution Overview
Problem
Existing methods for forming a coating layer on active materials in all-solid-state batteries result in thin, poorly dense layers, limiting evaluation and performance due to solvent evaporation creating pores, which hampers Li ion conduction and increases reaction resistance.
Innovation Solution
A method involving a coating step with a Li ion conductive oxide precursor solution, followed by heat treatment to form a precursor layer, and then compression shearing treatment to densify the coating layer, using metal alkoxides or peroxo complexes, and optimizing conditions such as heat treatment temperature and compression shearing energy to achieve a dense coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a coating layer is formed by heat treatment of a precursor solution, then the coating layer is formed on the active material surface, but the coating layer becomes non-dense with pores due to solvent evaporation
Solution Approach 1:
The invention applies compression shearing treatment before the final heat treatment step. This preliminary mechanical treatment densifies the coating structure by removing pores and aligning the coating material, preventing the formation of a porous structure that would occur if only heat treatment were applied. The compression shearing creates a dense precursor structure that subsequently forms a dense final coating.
Solution Approach 2:
The invention changes the physical state and density parameters of the coating layer by applying compression shearing treatment. This mechanical treatment alters the packing density, pore distribution, and structural parameters of the coating before heat treatment, resulting in a denser final product with reduced porosity compared to conventional heat treatment alone.
2Reliability
If the coating layer is thin to maintain active material performance, then the active material properties are preserved, but the coating layer becomes difficult to evaluate and its state remains unclear
Solution Approach 1:
The invention replaces conventional evaluation methods with compression shearing treatment that simultaneously densifies and characterizes the coating. The mechanical treatment process and its effects provide inherent information about coating density and quality, making thin coatings more evaluable through their response to and resulting from compression shearing, rather than relying on separate measurement techniques.
3Reliability
If conventional heat treatment is used to form the coating layer, then the Li ion conductive oxide is formed, but the coating layer remains non-dense leading to high reaction resistance
Solution Approach 1:
The compression shearing treatment is applied as a preliminary step before heat treatment to pre-densify the coating structure. This preliminary mechanical densification removes pores and improves the packing of coating material, so that when heat treatment forms the Li ion conductive oxide, the resulting coating has lower reaction resistance and better Li ion conduction than heat treatment alone could achieve.
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 method effectively produces active material composite particles with a dense coating layer, enhancing Li ion conduction and reducing reaction resistance by densifying the coating, thus improving battery performance.
Implementation Method 1
a heat treatment step of performing heat treatment on the precursor layer to form a coating layer comprising the Li ion conductive oxide
Implementation Method 2
a compression shearing treatment step of performing compression shearing treatment on the coating layer
Data Source
AI summary
An object of the present invention is to provide a method for producing active material composite particles having a dense coating layer. In the present invention, the above object is achieved by providing a method for producing an active material composite particle, the method comprising steps of: a coating step of coating a surface of an active material with a precursor solution of a Li ion conductive oxide to form a precursor layer; a heat treatment step of performing heat treatment on the precursor layer to form a coating layer comprising the Li ion conductive oxide; and a compression shearing treatment step of performing compression shearing treatment on the coating layer.