Battery Electrolyte Composition for Durable Negative Electrode Protection
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Solution Overview
Problem
Existing methods for protecting negative electrodes in non-aqueous electrolyte secondary batteries, such as forming protective films with silane-based compounds or adding additives to the electrolyte solution, lead to rapid degradation due to expansion and shrinkage, resulting in ineffective protection.
Innovation Solution
An electrolyte solution for non-aqueous electrolyte secondary batteries containing a silane compound with two or more trialkoxysilyl groups, which includes specific saturated hydrocarbon groups and is formulated at a concentration of 1×10³ to 1×10⁵ ppm, is used to impregnate the electrode assembly, providing enhanced protection against degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective film containing a silane-based compound is formed on the negative electrode surface, then negative electrode degradation is inhibited, but the film breaks during cycles due to expansion and shrinkage, leading to rapid degradation
Solution Approach 1:
The invention changes the chemical composition parameters of the protective film by incorporating specific silane compounds with two or more trialkoxysilyl groups into the electrolyte solution. This chemical parameter change enables the formation of a protective film with different mechanical properties that can withstand the expansion and shrinkage of alloy-based negative electrodes during cycling, thereby resolving the contradiction between initial protection effectiveness and long-term durability
Solution Approach 2:
The invention creates a composite protective film structure by combining silane compounds with specific molecular structures (containing two or more trialkoxysilyl groups) with the negative electrode surface. This composite material approach produces a film that integrates both protective functionality and mechanical flexibility, allowing it to maintain integrity during electrode expansion and shrinkage cycles while continuously protecting against degradation
2Reliability
If a silane-based additive is added to the electrolyte solution to protect the negative electrode, then negative electrode protection is achieved, but the additive is completely reduced and decomposed at the negative electrode, causing rapid degradation
Solution Approach 1:
The invention modifies the chemical structure parameters of the additive by selecting silane compounds with two or more trialkoxysilyl groups, which have different electrochemical stability characteristics compared to conventional silane additives. This parameter change in molecular structure enables the additive to form a stable protective film without being completely reduced and decomposed during cycling, thereby maintaining both protective function and long-term stability in the electrolyte solution
Solution Approach 2:
The invention replaces conventional silane additives that are completely consumed and decomposed (short-living) with silane compounds containing two or more trialkoxysilyl groups that form stable, self-replenishing protective films (long-living). This substitution transforms the additive from a disposable component that requires continuous replacement to a durable protective system that maintains effectiveness throughout battery cycling
3Reliability
If a silane-based additive is added to the electrolyte solution to protect the negative electrode, then negative electrode protection is intended, but the additive undergoes oxidative decomposition at the positive electrode, failing to protect the negative electrode
Solution Approach 1:
The invention changes the electrochemical potential window compatibility parameters by selecting silane compounds with two or more trialkoxysilyl groups that exhibit higher oxidation stability. This parameter change in chemical composition enables the additive to resist oxidative decomposition at the positive electrode while maintaining its protective function at the negative electrode, thereby eliminating the harmful side reaction that prevents effective negative electrode protection
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 electrolyte solution effectively inhibits negative electrode degradation, maintaining high capacity retention and low resistance increment even with alloy-based negative electrode active materials that undergo significant volume changes during charge and discharge cycles.
Implementation Method 1
forming a protective film containing a silane coupling agent on a surface of a negative electrode in a non-aqueous electrolyte secondary battery
Implementation Method 2
is used to impregnate the electrode assembly, providing enhanced protection against degradation
Data Source
AI summary
The present disclosure relates to an electrolyte solution for a non-aqueous electrolyte secondary battery comprising a silane compound having two or more trialkoxysilyl groups. By the present disclosure, an electrolyte solution for a non-aqueous electrolyte secondary battery capable of inhibiting degradation of a negative electrode in the non-aqueous electrolyte secondary battery is provided.