Cathode Mixture for All-Solid-State Battery Capacity
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Solution Overview
Problem
Current sulfur-based batteries face challenges in achieving high capacity due to low water resistance of materials like P2S5 and Li2S, which degrades battery performance.
Innovation Solution
A cathode mixture comprising sulfur, a sulfur-containing compound with elements like Ge, Sn, Si, B, or Al, and a conductive auxiliary material, with a Li element proportion of 4 mol% or less, is developed to enhance capacity and stability, using mechanical milling to create an ion conducting path and improve electron conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If Li2S is used as a cathode material to achieve high capacity, then the battery capacity increases, but the water resistance decreases leading to performance degradation
Solution Approach 1:
The patent uses composite materials by combining sulfur with metal sulfides (GeS2, SnS2, SiS2, B2S3, or Al2S3) to create a cathode mixture that achieves high capacity while maintaining water resistance. The composite structure allows the material to benefit from both the high capacity of sulfur and the stability of metal sulfides.
2Quantity of substance
If P2S5 is used as a cathode material to achieve high capacity, then the battery capacity increases, but the water resistance decreases leading to performance degradation
Solution Approach 1:
The patent replaces P2S5 with composite materials consisting of sulfur and metal sulfides (GeS2, SnS2, SiS2, B2S3, or Al2S3). These composite materials maintain high capacity while providing superior water resistance compared to P2S5, thereby resolving the contradiction between capacity and stability.
3Power
If mechanical milling is conducted to create ion conducting path and improve conductivity, then the electron conductivity increases, but the Li element proportion increases
Solution Approach 1:
The patent controls the Li element proportion parameter to be 4 mol% or less in the cathode mixture, while achieving high electron conductivity through mechanical milling of sulfur and metal sulfide composites. This parameter control allows improving conductivity without excessive Li content.
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 cathode mixture achieves high capacity and stability by minimizing Li content and utilizing materials with higher water resistance, such as Ge, Sn, and Si, resulting in improved charge and discharge performance.
Implementation Method 1
a mechanical milling step of conducting mechanical milling to the raw material mixture
Data Source
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Figure 3A~3C
Figure 4A~4C
AI summary
An object of the present disclosure is to produce a cathode mixture with high capacity. The present disclosure achieves the object by providing a cathode mixture characterized by comprising: a cathode active material including a S element; a sulfur containing compound including an M element, which is Ge, Sn, Si, B or Al, and a S element; a conductive auxiliary material; and substantially no Li element.