Carbon Negative Electrode Slurry Composition for Battery Swelling Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Secondary batteries face issues with electrolyte decomposition leading to cell swelling and increased internal resistance due to the high specific surface area of negative electrode active materials, which complicates slurry composition production and affects battery performance.
Innovation Solution
A slurry composition for secondary battery negative electrodes is developed using a carbon-based negative electrode active material with a specific surface oxygen atom-containing functional group content and a particulate polymer with controlled surface acid content, inhibiting excessive thickening and reducing contact interfaces with the electrolyte, thereby suppressing cell swelling and internal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the specific surface area of the negative electrode active material is reduced to suppress electrolyte decomposition, then cell swelling and internal resistance are reduced, but slurry composition production becomes difficult due to excessive thickening
Solution Approach 1:
The patent applies parameter changes by precisely controlling the surface oxygen functional group content (0.5-2.0% by weight) and specific surface area (0.5-3.0 m²/g) of the carbon-based negative electrode active material. This optimization resolves the contradiction by finding the optimal parameter range that suppresses electrolyte decomposition while maintaining slurry processability, preventing both excessive thickening and insufficient electrochemical performance.
Solution Approach 2:
The patent employs composite materials by combining carbon-based negative electrode active material with specific surface properties with a particulate polymer binder having controlled surface acid content (0.1-1.0 mmol/g). This composite approach allows the system to achieve both low electrolyte decomposition and good slurry producibility through the synergistic interaction between the optimized carbon material and the polymer binder.
2Object-affected harmful factors
If the specific surface area of the negative electrode active material is reduced to reduce contact interfaces with electrolyte, then cell swelling is suppressed, but rate characteristics deteriorate due to decreased sites for receiving charge carriers
Solution Approach 1:
The patent resolves this contradiction through parameter optimization by maintaining the specific surface area within 0.5-3.0 m²/g and surface oxygen functional group content at 0.5-2.0% by weight. This balanced parameter selection ensures sufficient contact interfaces for charge carrier reception while limiting excessive electrolyte decomposition, achieving both cell swelling suppression and acceptable rate characteristics.
Solution Approach 2:
The patent applies local quality by creating non-uniform surface properties on the carbon-based negative electrode active material through controlled oxygen functional group distribution. This allows different regions of the material surface to have optimized properties for either electrolyte interaction or charge carrier reception, resolving the contradiction between suppressing cell swelling and maintaining rate characteristics.
3Ease of manufacture
If the surface oxygen atom-containing functional group content is increased to improve slurry composition producibility, then excessive thickening is inhibited, but electrolyte decomposition increases leading to cell swelling
Solution Approach 1:
The patent resolves this contradiction through precise parameter control, limiting the surface oxygen atom-containing functional group content to 0.5-2.0% by weight. This optimized parameter range provides sufficient surface activity for slurry composition producibility and prevents excessive thickening, while simultaneously limiting electrolyte decomposition reactions that cause cell swelling.
Solution Approach 2:
The patent employs feedback by using surface oxygen functional groups as a controllable parameter that influences both slurry processability and electrochemical stability. By monitoring and controlling this parameter within the optimal range, the system achieves self-regulation where improved producibility does not lead to excessive electrolyte decomposition, resolving the contradiction between manufacturing ease and cell swelling suppression.
Data Source
Figure 1
AI summary
Provided is a slurry composition for a secondary battery negative electrode that has excellent producibility and can suppress cell swelling and an increase in internal resistance in a secondary battery. The slurry composition for a secondary battery negative electrode contains a negative electrode active material, a particulate polymer, and water. The negative electrode active material includes a carbon-based negative electrode active material having a surface functional group content of at least 0.9% and not more than 1.5%, and a BET specific surface area of 2.5 m2/g or less. The particulate polymer has a surface acid content of at least 0.2 mmol/g and not more than 2.0 mmol/g.