Polysaccharide Electrode Binders for Lithium-Ion Cells
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium ion battery electrodes using synthetic polymeric binders face issues with mechanical stability and capacitive performance degradation due to decontacting between electrochemically active particles and current collectors, leading to reduced battery life and environmental concerns from solvent use.
Innovation Solution
Development of electrodes with a matrix based on polysaccharides, such as cellulose derivatives, that form covalent bonds with electrochemically active particles, eliminating the need for synthetic polymeric compounds and enhancing mechanical stability and capacitive performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If synthetic polymeric binders (PVdF, PVdF-HFP) are used to ensure mechanical stability and particle contact, then the electrode maintains structural integrity, but capacity degradation occurs due to decontacting between particles and current collector over time
Solution Approach 1:
The invention changes the chemical bonding mechanism from physical adhesion (synthetic polymers) to covalent bonding (polysaccharides with electrochemically active particles). This parameter change in bonding strength and nature prevents decontacting between particles and current collector, maintaining both mechanical stability and capacitive performance over time
Solution Approach 2:
The invention creates a composite binder system using polysaccharides (such as carboxymethylcellulose) that combine mechanical binding properties with chemical bonding capability. This composite approach integrates the structural support function with the electrochemical stability function, resolving the contradiction between mechanical integrity and capacitive reliability
2Stability of the object's composition
If fluorinated polymer binders are used to maintain electrode structure, then mechanical stability is achieved, but environmental harm increases due to required organic solvents (N-methylpyrrolidin-2-one, acetone)
Solution Approach 1:
The invention changes the processing medium from organic solvents to water as a solvent for polysaccharide binders. This parameter change eliminates the need for hazardous organic solvents like N-methylpyrrolidin-2-one and acetone, thereby reducing environmental impact while maintaining the mechanical stability function of the binder
Solution Approach 2:
The invention converts the traditionally harmful organic solvent requirement into a benefit by using water-soluble polysaccharides. This eliminates environmental harm associated with fluorinated polymer processing while maintaining effective binder performance, turning a harmful process requirement into an environmentally friendly solution
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 polysaccharide-based electrodes exhibit improved mechanical stability and prolonged capacitive performance, reducing capacity degradation and environmental impact by eliminating the use of hazardous solvents and synthetic polymers.
Implementation Method 1
the particles are joined to the matrix by covalent bonds
Data Source
AI summary
An electrode for a lithium ion battery includes a matrix based on at least one polysaccharide and also particles of at least one electrochemically active material which are embedded in the matrix, with the electrode being free of synthetic polymeric compounds. A battery contains the electrode and a polysaccharide is a binder for electrochemically active electrode materials for such an electrode.