Negative Electrode Electrolyte Composition for Low-Gas Secondary Batteries
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Solution Overview
Problem
Secondary batteries face challenges in cycle performance, storage performance, and safety performance, particularly in terms of gas production during cycling, which affect their overall efficiency and reliability.
Innovation Solution
The use of an ethylene carbonate solvent and a cyclic sulfate compound as an additive in a non-aqueous electrolyte solution, combined with a negative electrode active material of specific particle size, forms a stable inorganic and organic mixed solid electrolyte interface (SEI) film on the negative electrode, reducing gas production and enhancing cycle and storage performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolyte solutions are used, then the battery can operate, but gas production occurs during cycling reducing performance
Solution Approach 1:
The cyclic sulfate compound acts as an intermediary substance that mediates between the electrolyte solution and the negative electrode. It forms a stable SEI film that prevents direct harmful reactions between the electrolyte and electrode, thereby reducing gas production while maintaining battery operation. The additive concentration of 0.01-5% by mass optimizes this intermediary function.
Solution Approach 2:
The invention changes the chemical composition parameters of the electrolyte solution by introducing cyclic sulfate compounds with specific molecular structures (Formula I with various R groups). This parameter change transforms the electrolyte's interaction with the negative electrode, leading to reduced gas production during cycling while maintaining electrical conductivity.
2Duration of action of moving object
If the battery operates for extended cycles, then energy storage capacity is utilized, but performance degradation occurs
Solution Approach 1:
The cyclic sulfate compound performs preliminary action by forming a stable SEI film during initial cycles or upon first contact with the negative electrode. This pre-formed protective layer prevents subsequent degradation reactions, ensuring performance stability throughout the battery's operational life. The film formation occurs before significant capacity loss can occur.
Solution Approach 2:
The electrolyte solution becomes a composite system combining conventional non-aqueous solvents with cyclic sulfate compound additives. This composite electrolyte provides both the ionic conductivity of traditional electrolytes and the protective film-forming capabilities of the cyclic sulfate additive, achieving extended cycle life with stable performance.
3Reliability
If standard electrolyte composition is used, then conductivity is maintained, but storage performance deteriorates
Solution Approach 1:
The invention optimizes the concentration parameter of cyclic sulfate compounds (0.01-5% by mass) to achieve a balance between storage performance and conductivity. At these optimized concentrations, the additive provides sufficient protective film formation for improved storage stability while maintaining adequate ionic conductivity for battery operation.
Solution Approach 2:
The cyclic sulfate compound creates a stable SEI film that copies or replicates the ideal protective interface between electrolyte and electrode. This film serves as a stable intermediary layer that prevents degradation during storage while allowing necessary ionic transport, effectively copying the properties of a theoretically perfect interface.
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 solution inhibits gas production, improves cycle performance, and enhances storage performance by forming a more stable SEI film with stronger electron blocking ability, while also promoting lithium salt dissociation for better conductivity.
Implementation Method 1
ethylene carbonate and an additive form a more stable inorganic and organic mixed SEI film on the surface of a negative electrode with a stronger electron blocking ability
Implementation Method 2
form a more stable inorganic and organic mixed SEI film on the surface of a negative electrode with a stronger electron blocking ability
Implementation Method 3
ethylene carbonate may promote the dissociation of lithium salts in the electrolyte solution to improve the conductivity of the electrolyte solution
Data Source
AI summary
A secondary battery and an electrical apparatus are disclosed. The secondary battery includes a negative electrode plate and a non-aqueous electrolyte solution. The negative electrode plate includes a negative electrode active material. The volume average particle size Dv50 of the negative electrode active material is 6-20 μm. The non-aqueous electrolyte solution includes an additive and a non-aqueous solvent. The additive includes a cyclic sulfate compound represented by Formula (I). The non-aqueous solvent includes ethylene carbonate.