Nonaqueous Electrolyte Additive Blends for SEI Stability and Low Gas
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Solution Overview
Problem
Nonaqueous electrolyte solutions using existing additives fail to adequately extend the lifespan and suppress gas generation in electricity storage devices.
Innovation Solution
A nonaqueous electrolyte solution containing a specific cyclic sulfone compound combined with at least one of an ethylene carbonate compound, a vinyl ethylene carbonate compound, a cyclic sulfonic acid ester compound, or a cyclic disulfonic acid ester compound, forming a stable solid electrolyte interface to enhance battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing additives are used in nonaqueous electrolyte solutions, then battery performance is maintained, but lifespan extension and gas generation suppression are insufficient
Solution Approach 1:
The patent modifies the chemical structure parameters of the additive by introducing a specific cyclic sulfone compound with formula (1) where X is a sulfonyl group or carbonyl group, and R1 is a specific substituent pattern. This structural parameter change enables the additive to form a more stable SEI film that simultaneously extends lifespan and suppresses gas generation, resolving the contradiction between these two performance aspects.
Solution Approach 2:
The patent creates a composite additive system by combining the cyclic sulfone compound of formula (1) with at least one compound from formula (2-1) to (2-4). This composite approach allows the different compounds to work synergistically, where the cyclic sulfone provides baseline stability while the additional compound enhances both lifespan and gas suppression properties beyond what either compound could achieve alone.
2Reliability
If various additives are added to form SEI during first charge/discharge, then electricity storage device deterioration is prevented, but gas generation is not sufficiently suppressed
Solution Approach 1:
The patent changes the chemical composition parameters of the SEI-forming additive by using the specific cyclic sulfone compound structure with sulfonyl or carbonyl group. This structural modification alters the decomposition behavior during first charge/discharge, creating an SEI film that is both protective against deterioration and effective at suppressing gas generation, thus resolving the contradiction between these two functions.
3Duration of action of stationary object
If conventional electrolyte solution additives are used, then charge/discharge cycle characteristics are improved, but both lifespan extension and gas generation suppression cannot be satisfied simultaneously
Solution Approach 1:
The patent modifies the additive's molecular structure parameters by employing the cyclic sulfone compound with specific substituents (R1 groups) and functional groups (X). This structural parameter change enhances the additive's ability to form a stable SEI that improves cycle characteristics while simultaneously suppressing gas generation, resolving the contradiction between duration of action and harmful factor suppression.
Solution Approach 2:
The patent develops a composite additive formulation combining the cyclic sulfone compound (formula 1) with compounds of formula (2-1) to (2-4). This composite material approach allows the synergistic interaction between components to achieve both improved cycle characteristics and gas generation suppression, satisfying both requirements that conventional single additives cannot meet simultaneously.
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 effectively extends the lifespan and suppresses gas generation in electricity storage devices, particularly when used with lithium-containing composite oxides as positive electrodes, improving capacity retention and reducing resistance.
Implementation Method 1
The additives are decomposed during a first charge/discharge to form a film called a solid electrolyte interface (SEI) on a surface of an electrode
Implementation Method 2
the lithium ions can be transferred between electrodes through the SEI
Data Source
Figure 1
AI summary
Disclosed is an additive for nonaqueous electrolyte solutions, including a first compound represented by the formula (1), and at least one second compound selected from the group consisting of an ethylene carbonate compound, a vinyl ethylene carbonate compound, a cyclic sulfonic acid ester compound, and a cyclic disulfonic acid ester compound, in the formula (1), X represents a sulfonyl group or a carbonyl group, and R1 represents an alkyl group having 1 to 4 carbon atoms and optionally substituted with a halogen atom or the like.