Lithium-Replenishing Polyacrylate Binder for Li-Ion Battery Electrodes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium-ion batteries face reduced efficiency during the first charging and discharging process due to the generation of the SEI film on the negative electrode and side reactions with dead lithium and impurities in the positive electrode material, affecting cycling and rate performance.
Innovation Solution
A binder comprising a polyacrylate copolymer and a lithium-containing compound is used, which acts as both a binder and a lithium replenisher, enhancing bonding performance, ionic conductivity, and facilitating rapid lithium replenishment, eliminating the need for a separate lithium metal layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate lithium metal layer or lithium replenishment layer is added to compensate for lithium loss, then lithium replenishment effect is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent combines the binder and lithium replenishment functions into a single integrated binder material containing lithium source compounds (such as lithium hydroxide, lithium oxide, or lithium carbonate). This eliminates the need for separate lithium metal layers or replenishment layers, thereby maintaining effective lithium replenishment while reducing structural complexity and manufacturing difficulty.
Solution Approach 2:
The binder serves multiple functions simultaneously: it acts as an adhesive to hold electrode materials together, provides lithium replenishment to compensate for lithium loss during cycling, and maintains electrode structural integrity. This multi-functionality resolves the contradiction by eliminating the need for additional dedicated lithium replenishment components.
2Reliability
If conventional binders are used, then manufacturing simplicity is maintained, but bonding performance and ionic conductivity are insufficient
Solution Approach 1:
The patent employs a composite binder system consisting of a base binder (such as polyvinylidene fluoride or carboxymethyl cellulose) combined with lithium-containing compounds (such as lithium hydroxide, lithium oxide, or lithium carbonate). This composite material provides superior bonding performance and ionic conductivity compared to conventional binders, while the components can be easily mixed and applied using existing manufacturing processes.
Solution Approach 2:
The invention modifies the chemical composition parameters of the binder by incorporating specific lithium-containing compounds in optimized ratios. This changes the binder's properties to achieve enhanced bonding strength and ionic conductivity, while the modification process remains compatible with conventional manufacturing methods requiring only simple mixing and coating steps.
3Reliability
If first charging and discharging efficiency is improved by reducing SEI film generation, then cycling performance is enhanced, but initial capacity is reduced
Solution Approach 1:
The binder containing lithium source compounds performs preliminary lithium replenishment action during the first charging and discharging cycles. By providing a lithium reservoir in the binder, the system compensates for lithium consumed in SEI film formation and side reactions, thereby improving cycling performance without permanently reducing the available lithium capacity for subsequent cycles.
Solution Approach 2:
The lithium-containing binder acts as a sacrificial lithium source that gradually releases lithium ions during initial cycles to compensate for losses. This recovered lithium from the binder replenishes the electrode materials, effectively recovering the capacity lost to SEI film formation and side reactions, thereby improving cycling performance while maintaining usable 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 binder improves the cycling and rate performance of lithium-ion batteries by reducing electrochemical impedance and increasing ion transfer speed, while maintaining structural stability during cycling.
Implementation Method 1
the polymer possesses excellent anti-swelling ability. This also facilitates a good bonding effect, enhances ionic conductivity, and helps control molecular weight and glass transition temperature of the polymer
Implementation Method 2
the binder facilitates rapid replenishment of consumed lithium ions in the lithium battery, thereby increasing the ion transfer speed and enhancing structural stability
Data Source
AI summary
A binder includes a polyacrylate copolymer and a lithium-containing compound. A preparation method of a binder includes adding monomers of a polyacrylate copolymer to a first emulsifier solution to obtain a pre-emulsion, adding an initiator to the pre-emulsion for reaction to obtain a reaction solution, and adding a lithium-containing substance to the reaction solution to adjust pH value to 7 to 8 and performing filtering to obtain the binder.