Sulfonic Acid Coated Battery Electrode for High-Temperature Stability
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Solution Overview
Problem
Existing nonaqueous electrolyte secondary batteries face challenges in achieving high capacity and improving charge-discharge cycle characteristics, particularly in applications requiring long-term high-temperature storage.
Innovation Solution
Incorporating a lithium-containing composite oxide with a sulfonic acid compound on its surface and a sulfur-containing compound in the nonaqueous electrolyte, forming a protective barrier that suppresses side reactions and enhances the battery's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a lithium-containing composite oxide is used as the positive electrode active material, then the battery capacity can be increased, but the charge-discharge cycle characteristics and resistance stability deteriorate due to side reactions at high temperature
Solution Approach 1:
A sulfonic acid compound is introduced as an intermediary substance that forms a protective interface layer between the lithium-containing composite oxide and the nonaqueous electrolyte. This intermediary layer suppresses harmful side reactions while allowing beneficial ionic conduction, thereby improving charge-discharge cycle characteristics without sacrificing battery capacity.
Solution Approach 2:
The positive electrode active material is designed as a composite structure combining lithium-containing composite oxide with a sulfonic acid compound coating. This composite material approach allows the core oxide to provide high capacity while the surface coating provides stability and resistance suppression, resolving the contradiction between capacity and cycle characteristics.
2Duration of action of stationary object
If the battery is stored at high temperature for a long term, then the resistance change increases, but the sulfonic acid compound coating helps suppress this resistance change
Solution Approach 1:
The sulfonic acid compound coating is applied in advance to the lithium-containing composite oxide surface before battery assembly and storage. This preliminary protective action creates a stable interface that prevents resistance increase during subsequent high-temperature long-term storage, counteracting the harmful effects before they can occur.
Solution Approach 2:
The sulfonic acid compound forms a thin, sacrificial protective layer that can be consumed or degraded during storage, but this short-living coating effectively suppresses resistance change throughout the storage period, providing economical protection against long-term degradation.
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 combination of a sulfonic acid compound on the lithium-containing composite oxide surface and a sulfur-containing compound in the electrolyte significantly improves the battery's capacity and cycle characteristics, reducing resistance and maintaining performance over time.
Implementation Method 1
a sulfonic acid compound present on a surface of the lithium-containing composite oxide
Implementation Method 2
the nonaqueous electrolyte contains a sulfur-containing compound
Data Source
AI summary
A nonaqueous electrolyte secondary battery includes a positive electrode, a negative electrode, and a nonaqueous electrolyte. The positive electrode includes a positive electrode active material. The positive electrode active material includes a lithium-containing composite oxide, and a sulfonic acid compound present on a surface of the lithium-containing composite oxide. The nonaqueous electrolyte contains a sulfur-containing compound.