Solid-State Battery Cathode Material Optimizing Ion Exchange
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Solution Overview
Problem
Current all-solid-state lithium-ion batteries face challenges in achieving smooth lithium ion exchange and improved cycle characteristics with existing positive electrode active materials, which are not effectively addressed by research findings from liquid-type lithium-ion batteries.
Innovation Solution
A positive electrode active material with a lithium metal composite oxide having a layered structure, a transition metal, and specific composition and structural requirements, including a minimum average crush strength of 50 MPa and a particle size distribution, is developed to enhance lithium ion exchange and battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional positive electrode active materials from liquid-type lithium-ion batteries are used in all-solid-state lithium-ion batteries, then the material composition is well-established, but smooth lithium ion exchange and cycle characteristics are not achieved
Solution Approach 1:
The patent applies parameter changes by optimizing the particle size distribution (D10-D90 range of 3-15 μm) and crush strength (≥50 MPa) of the positive electrode active material. These parameter adjustments enable smooth lithium ion exchange at the interface with solid electrolyte while maintaining structural stability during cycling, directly resolving the contradiction between reliable cycle performance and effective lithium ion exchange.
Solution Approach 2:
The patent employs composite materials by creating a positive electrode active material with specific composite oxide composition (Li-containing metal composite oxide) that combines multiple metal elements. This composite structure provides both the chemical stability needed for good cycle characteristics and the physical properties (particle strength and size distribution) required for efficient lithium ion exchange with solid electrolyte.
2Adaptability or versatility
If research findings from liquid-type lithium-ion batteries are applied to all-solid-state lithium-ion batteries, then existing material knowledge is utilized, but the specific requirements of solid-state batteries are not met
Solution Approach 1:
The patent applies local quality by specifying particular properties for the positive electrode active material that are tailored to solid-state battery requirements. Instead of using general liquid-type battery materials, the invention defines local characteristics including particle size distribution (3-15 μm), crush strength (≥50 MPa), and specific oxide composition that are optimized for the local conditions at the solid electrolyte interface, thereby achieving both adaptability and reliable performance.
3Ease of manufacture
If positive electrode active material with insufficient crush strength is used, then material processing is easier, but particle integrity and lithium ion exchange are compromised
Solution Approach 1:
The patent resolves this contradiction through parameter changes by establishing the minimum crush strength parameter of 50 MPa for the positive electrode active material particles. This parameter threshold ensures that particles maintain sufficient integrity during processing and operation while still allowing effective lithium ion exchange. The specific particle size range (3-15 μm) is also optimized to balance processability with structural integrity.
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 new positive electrode active material enables efficient lithium ion exchange and improves cycle characteristics, reducing capacity loss and maintaining high performance in all-solid-state lithium-ion batteries.
Implementation Method 1
lithium ions are exchanged between the positive electrode active material and the solid electrolyte
Data Source
Figure 1~2
AI summary
The present invention provides a positive electrode active material for an all-solid-state lithium-ion battery, an electrode, and an all-solid-state lithium-ion battery capable of smoothly exchanging lithium ions with a solid electrolyte at a positive electrode and improving battery performance. A positive electrode active material for an all-solid-state lithium-ion battery formed of particles includes crystals of a lithium metal composite oxide, in which the lithium metal composite oxide has a layered structure and contains at least Li and a transition metal, and the particles have an average crush strength of more than 50 MPa and satisfy Expression (1). 1.0µm≤Dmin [Selection diagram] None