Negative Electrode Binder Composition for Stable Lithium Occlusion
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Solution Overview
Problem
Current secondary batteries do not achieve optimal battery characteristics, such as efficient lithium occlusion and release, due to limitations in the composition and structure of their negative electrode components.
Innovation Solution
A secondary battery design featuring a negative electrode with a binder copolymer of acrylamide, lithium acrylate, and acrylonitrile, where the surface analysis using X-ray photoelectron spectroscopy indicates specific concentration ratios of carbon, nitrogen, and lithium, optimizing the coating film's composition and improving the electrode's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional negative electrode binders are used, then the battery structure is simple and easy to manufacture, but the battery characteristics such as lithium occlusion and release efficiency are insufficient
Solution Approach 1:
The negative electrode binder uses a copolymer composed of acrylamide, lithium acrylate, and acrylonitrile units. This composite polymer structure combines the advantages of different monomer units to achieve both good adhesion and flexible expansion/contraction properties, resolving the contradiction between simple structure and excellent battery characteristics
Solution Approach 2:
The invention specifies precise compositional parameters for the copolymer binder, including the presence of specific functional groups and controlled ratios of different monomer units. These parameter optimizations enable the binder to form coating films with specific concentration ratios of carbon, nitrogen, and lithium, thereby improving lithium occlusion and release efficiency without excessive structural complexity
2Productivity
If the negative electrode binder composition is optimized for better lithium occlusion and release, then battery characteristics improve, but the manufacturing complexity increases
Solution Approach 1:
The copolymer binder is designed with specific compositional parameters (acrylamide, lithium acrylate, and acrylonitrile units in controlled ratios) that can be achieved through standard polymerization processes. The specification of functional group content and monomer ratios provides clear manufacturing targets while maintaining feasibility through conventional polymer synthesis methods
3Reliability
If a coating film is added to the negative electrode active material layer, then battery characteristics improve, but the device structure becomes more complex
Solution Approach 1:
The copolymer binder serves multiple functions simultaneously: it acts as the binding agent holding the active material together, provides the coating film on the active material surface, and contributes lithium ions through the lithium acrylate units. This multi-functionality eliminates the need for separate coating layers, improving capacity retention while avoiding excessive structural complexity
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
This configuration enhances the battery's charge-discharge efficiency, reduces irreversible capacity, and stabilizes lithium occlusion and release, resulting in improved battery characteristics and capacity retention.
Implementation Method 1
surface analysis of the negative electrode using X-ray photoelectron spectroscopy
Data Source
AI summary
A secondary battery is provided and includes a positive electrode, a negative electrode, and an electrolytic solution. The negative electrode includes a negative electrode active material layer containing a negative electrode binder and a coating film provided on a surface of the negative electrode active material layer, and the negative electrode binder contains a copolymer of acrylamide, lithium acrylate, and acrylonitrile. A C1s spectrum, an N1s spectrum, and an Li1s spectrum are detected by surface analysis of the negative electrode using X-ray photoelectron spectroscopy, a first concentration ratio as calculated by Equation (1) is 0.4 or more and 2.7 or less, and a second concentration ratio as calculated by Equation (2) is 3.4 or more and 5.9 or less.