Cathode Particle Coating With Amorphous Lithium Conductor
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Solution Overview
Problem
Existing lithium ion secondary battery technologies face limitations in reducing battery resistance due to the need for high-temperature treatments and the inferior lithium ion conductivity of crystalline coatings, which restrict the reduction of reaction resistance.
Innovation Solution
A method involving the production of a wet mixture with lithium-containing positive electrode active material particles coated with an amorphous lithium conductor and dispersed ferroelectric ceramic particles, where the ceramic particles are larger than the coating thickness, enhancing lithium ion transfer during charging and discharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coating made of crystalline lithium ion conductor is formed on the surface of positive electrode active material particles, then the coating can be formed through high-temperature treatment, but the lithium ion conductivity is lower compared to amorphous lithium ion conductor
Solution Approach 1:
The patent changes the physical state parameter of the lithium ion conductor coating from crystalline to amorphous phase. This parameter change enables the coating to achieve superior lithium ion conductivity without requiring high-temperature treatment, thus resolving the contradiction between conductivity and treatment temperature.
Solution Approach 2:
The patent replaces the thermal field (high-temperature treatment) with a chemical field approach by using solution-based coating methods. The amorphous lithium ion conductor is applied through solution processing and drying, substituting the mechanical/thermal formation process with a chemical solution process that achieves better conductivity at lower temperatures.
2Stability of the object's composition
If high-temperature treatment is applied to form the coating, then the coating structure can be stabilized, but the production costs increase
Solution Approach 1:
The patent changes the formation temperature parameter from high-temperature (700°C) to low-temperature processing. The amorphous coating is formed through solution application and drying at moderate temperatures, eliminating the need for energy-intensive high-temperature treatment while maintaining coating stability and reducing production costs.
Solution Approach 2:
The patent replaces the thermal stabilization process with a chemical solution process. The coating is applied in solution form and stabilized through controlled drying and potential low-temperature treatment, substituting the high-temperature thermal field with a chemical field approach that reduces energy consumption and manufacturing costs.
3Reliability
If ferroelectric particles with size equal to or smaller than the coating are used, then the coating can be uniformly formed, but the reduction of battery resistance is limited
Solution Approach 1:
The patent changes the size parameter of ferroelectric particles from sub-coating-size to super-coating-size. This parameter change allows particles larger than the coating thickness to protrude from the coating surface, creating additional active sites for lithium ion transfer and enhancing battery performance beyond what is achievable with smaller particles.
Solution Approach 2:
The patent creates local quality variation in the coating structure by incorporating ferroelectric particles of different sizes. The larger particles protruding from the coating surface create localized regions of enhanced lithium ion conductivity and electrochemical activity, while the coating matrix provides uniform coverage. This local quality differentiation optimizes both uniformity and performance.
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 reduces the reaction resistance of the positive electrode plate and consequently the lithium ion secondary battery by facilitating smoother lithium ion movement through the amorphous lithium conductor and polarized ferroelectric ceramic particles, improving battery performance without the need for high-temperature treatments.
Implementation Method 1
a coating which is made of an amorphous lithium conductor and in which the ferroelectric ceramic particles are dispersed on the surface of the lithium-containing positive electrode active material particles
Implementation Method 2
crystalline ferroelectric ceramic particles are dried, stirred and mixed to obtain a mixed powder
Data Source
AI summary
A method of producing a wet mixture includes a stirring and mixing process in which lithium-containing positive electrode active material particles having surplus lithium compounds on the surface and crystalline ferroelectric ceramic particles are dried, stirred and mixed to obtain a mixed powder; and a solution mixing process in which a lithium conductor forming solution is mixed with the mixed powder to obtain a wet mixture containing coated lithium-containing positive electrode active material particles having a coating which is made of an amorphous lithium conductor and in which the ferroelectric ceramic particles are dispersed on the surface of the lithium-containing positive electrode active material particles.