Lithium Battery Positive Electrode Binder Composition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Rechargeable lithium batteries face challenges in achieving high capacity and excellent performance due to the trade-off between binding force and flexibility of the electrode, as high active material density leads to thicker electrodes, compromising safety and flexibility.
Innovation Solution
A positive electrode for rechargeable lithium batteries is developed using a binder composition that includes polyvinylidene fluoride, carboxyl group-containing polyvinylidene fluoride, and poly(vinylidene-fluoride-tetrafluoroethylene) in specific weight ratios, which improves both binding force and flexibility, thereby enhancing battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high active material density is used to secure high capacity, then battery capacity is improved, but electrode thickness increases and flexibility deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the binder by incorporating carboxyl group-containing polyvinylidene fluoride and poly(vinylidenefluoride-tetrafluoroethylene) in specific weight ratios. This chemical parameter change enables the electrode to maintain flexibility even at high active material density (95-98 wt%), resolving the contradiction between capacity and flexibility.
Solution Approach 2:
The patent uses a composite binder system combining three components: polyvinylidene fluoride (60-80 wt%), carboxyl group-containing polyvinylidene fluoride (5-20 wt%), and poly(vinylidenefluoride-tetrafluoroethylene) (5-20 wt%). This composite material approach provides both strong binding force for high capacity and sufficient flexibility, simultaneously addressing both requirements.
2Quantity of substance
If high active material density is used to secure high capacity, then battery capacity is improved, but binding force deteriorates
Solution Approach 1:
The patent optimizes the weight ratio parameters of the binder components, specifically setting carboxyl group-containing polyvinylidene fluoride at 5-20 wt% and poly(vinylidenefluoride-tetrafluoroethylene) at 5-20 wt%. These parameter changes enhance binding force through carboxyl group interactions while maintaining high active material density for high capacity.
Solution Approach 2:
The composite binder system provides synergistic effects where polyvinylidene fluoride forms the base matrix, carboxyl group-containing polyvinylidene fluoride enhances adhesion through carboxyl groups, and poly(vinylidenefluoride-tetrafluoroethylene) provides structural support. This composite approach simultaneously improves binding force and maintains flexibility at high capacity densities.
Data Source
AI summary
A positive electrode for a rechargeable lithium battery includes a positive active material and a binder including polyvinylidene fluoride, a carboxyl group-containing polyvinylidene fluoride, and poly(vinylidenefluoride-tetrafluoroethylene). The positive electrode may have an improved binding force and increased flexibility. A rechargeable lithium battery includes the positive electrode. The rechargeable lithium battery may have high capacity and excellent performance.