Lithium Ion Battery Positive Electrode Coating with Ferroelectric Dispersion
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Solution Overview
Problem
Existing positive electrode materials for lithium ion secondary batteries coated with ferroelectric substances suffer from poor lithium ion conductivity, leading to blocked ion insertion and desorption, which decreases the effective reaction area and reduces the effectiveness of battery resistance reduction.
Innovation Solution
A method of manufacturing a positive electrode material by forming a coat that includes a lithium ion conductor and a ferroelectric substance, where the ferroelectric substance is dispersed in the lithium ion conductor, and the lithium ion conductor is interposed between the positive electrode active material and the ferroelectric substance, forming a composite material that enhances lithium ion diffusion and reduces battery resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the positive electrode active material is directly coated with ferroelectric substance, then battery resistance is reduced, but effective reaction area is decreased
Solution Approach 1:
By using a composite coating structure where ferroelectric particles are dispersed in a lithium ion conductor matrix, the patent maintains a larger effective reaction area compared to direct coating. The conductor matrix provides conductive pathways while the dispersed ferroelectric particles provide the resistance-reducing effect, thus resolving the contradiction between resistance reduction and maintaining reaction area.
Solution Approach 2:
The patent applies local quality by having ferroelectric substance particles distributed throughout the lithium ion conductor matrix rather than forming a continuous layer. This localized distribution allows different regions of the coating to have different functions: the conductor matrix provides ion transport and maintains reaction area, while the ferroelectric particles provide resistance reduction at their specific locations.
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 method effectively increases the lithium ion diffusion path and reduces battery resistance, improving the battery's performance and cycle durability by preventing the effective reaction area from being decreased due to direct coating with the ferroelectric substance.
Implementation Method 1
the Li ion conductor is interposed at least partially between the positive electrode active material and the ferroelectric substance... facilitate diffusion of Li ions
Implementation Method 2
it is expected to facilitate diffusion of Li ions by dielectric polarization (alignment of electric dipole) of the ferroelectric substance in the diffusion path (Li ion conductor)
Data Source
AI summary
A method of manufacturing a positive electrode material for lithium ion secondary battery includes the following (α) and (β): (α) a positive electrode active material is prepared; and (β) the positive electrode material for lithium ion secondary battery is manufactured by forming a coat on at least a portion of a surface of the positive electrode active material. The coat is formed to satisfy the following (1) to (3): (1) the coat includes a lithium ion conductor and a ferroelectric substance; (2) the ferroelectric substance is dispersed in the lithium ion conductor; and (3) the lithium ion conductor is interposed at least partially between the positive electrode active material and the ferroelectric substance.