Nonaqueous Electrolyte Battery Styrene Binder and Cyclic Sulfonic Acid Ester
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Solution Overview
Problem
Lithium secondary batteries face issues with capacity retention under high temperature environments due to insufficient stability between electrode active materials and electrolytic solutions, leading to increased resistance and decreased battery performance over repeated charge and discharge cycles.
Innovation Solution
A nonaqueous electrolyte secondary battery design incorporating a negative electrode with a styrene polymer binder (0.3 to 8.0 mass%) and a cyclic sulfonic acid ester (0.002 to 5.0 mass%) in the electrolytic solution, forming a stable ion-conductive film that prevents side reactions and maintains adhesiveness, allowing for smooth lithium ion transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolytic solutions are used in lithium secondary batteries, then charge and discharge can be performed, but side reactions occur between the electrolytic solution and electrode active materials under high temperature environments, leading to increased resistance and decreased capacity retention
Solution Approach 1:
The patent introduces a cyclic carboxylate compound as an intermediary substance in the electrolytic solution. This compound acts as a mediator that forms a protective film on the electrode surface, preventing direct contact and harmful side reactions between the electrolytic solution and electrode active materials. The cyclic carboxylate compound specifically coordinates with metal ions at the electrode-electrolyte interface, creating a stable interfacial layer that eliminates harmful side reactions while maintaining ionic conductivity.
Solution Approach 2:
The patent employs a composite electrolytic solution system combining conventional electrolytes (such as LiPF6 in carbonate solvents) with cyclic carboxylate compounds. This composite approach integrates the high ionic conductivity of conventional electrolytes with the protective film-forming capability of cyclic carboxylates, achieving both efficient charge-discharge performance and enhanced stability against side reactions under high temperature conditions.
2Power
If the battery operates under high temperature environments for extended periods, then power delivery can be maintained, but electrode adhesiveness deteriorates and resistance increases, reducing battery life
Solution Approach 1:
The cyclic carboxylate compound performs preliminary protective action by forming a stable interfacial film on the electrode surface before harmful high-temperature degradation occurs. This pre-formed protective layer prevents subsequent deterioration of electrode adhesiveness and resists the formation of high-resistance layers, thereby extending battery life while maintaining power delivery capability under high temperature operation.
Solution Approach 2:
The patent modifies the chemical composition parameters of the electrolytic solution by incorporating cyclic carboxylate compounds with specific molecular structures and concentrations. This parameter change transforms the interfacial chemistry between electrode and electrolyte, creating a more thermally stable interface that maintains low resistance and good adhesiveness even after prolonged high-temperature operation.
3Productivity
If conventional electrolytic solutions are used, then initial battery performance can be achieved, but decomposition reactions occur between the electrolyte and carbon material, leading to capacity fade over time
Solution Approach 1:
The patent converts the potentially harmful decomposition reactions between conventional electrolytes and carbon electrode materials into beneficial effects. The cyclic carboxylate compound preferentially reacts with trace water and impurities in the electrolyte system, forming stable products that prevent subsequent decomposition at the carbon electrode interface. This transforms what would be harmful decomposition reactions into a protective preprocessing action that preserves battery capacity.
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 ensures high capacity retention rates even after prolonged use under high temperature conditions by preventing side reactions and maintaining electrode adhesiveness, thus enhancing the battery's performance and longevity.
Implementation Method 1
forming a stable ion-conductive film that prevents side reactions
Implementation Method 2
a cyclic sulfonic acid ester including two sulfonyl groups is contained in an amount of 0.002 to 5.0 mass% based on a total mass of the nonaqueous electrolytic solution
Implementation Method 3
maintaining electrode adhesiveness, allowing for smooth lithium ion transfer
Implementation Method 4
a negative electrode with a styrene polymer binder (0.3 to 8.0 mass%)
Implementation Method 5
a positive electrode capable of absorbing and desorbing a lithium ion; a negative electrode comprising a negative electrode active material layer containing at least a styrene polymer as a binder and capable of absorbing and desorbing the lithium ion
Data Source
Figure 1
AI summary
A nonaqueous electrolyte secondary battery comprising positive and negative electrodes capable of absorbing and desorbing lithium ions; a nonaqueous electrolytic solution; and a separator provided between the positive electrode and the negative electrode. The negative electrode comprises a negative electrode active material layer containing at least a styrene polymer as a binder in a content of 0.3 to 8.0 mass% based on the total mass of the negative electrode active material layer. The nonaqueous electrolytic solution contains at least a cyclic sulfonic acid ester including two sulfonyl groups in a content of 0.002 to 5.0 mass% based on the total mass of the nonaqueous electrolytic solution.