Battery Binder Composition for Transition Metal Ion Capture
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In secondary batteries using transition metal-containing positive electrode active materials, there is a concern about transition metal ions eluting into the electrolyte solution and depositing on the negative electrode, which negatively impacts battery characteristics such as cycle performance, with existing techniques focusing insufficiently on this issue.
Innovation Solution
A binder composition for non-aqueous secondary batteries is developed, comprising a water-soluble polymer with a sulfonate group-containing monomer unit in 10-50 mass% and a (meth)acrylonitrile monomer unit in 20-50 mass%, which forms electrode or functional layers with high transition metal capturing ability, improving adhesiveness and cycle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If transition metal-containing positive electrode active materials are used to increase secondary battery capacity, then battery capacity is improved, but transition metal ions elute into electrolyte solution and deposit on negative electrode, deteriorating cycle characteristics
Solution Approach 1:
A functional layer containing a water-soluble polymer with specific monomer units (sulfonate group-containing and (meth)acrylonitrile) is introduced as an intermediary between the positive and negative electrodes. This functional layer captures transition metal ions that elute from the positive electrode, preventing their deposition on the negative electrode and thus maintaining cycle characteristics while allowing the use of high-capacity transition metal-containing materials.
2Reliability
If a functional layer is introduced to capture transition metal ions, then cycle characteristics are improved, but device structure becomes more complex
Solution Approach 1:
The functional layer is merged with existing battery components such as the separator or electrode structures. The water-soluble polymer is applied to form the functional layer on these existing components, combining multiple functions (ion capture, structural support, and electrochemical stability) into a single integrated component, thereby reducing overall device complexity.
3Reliability
If a water-soluble polymer with sulfonate groups and (meth)acrylonitrile units is used as binder, then transition metal capturing ability is improved, but manufacturing process becomes more complex
Solution Approach 1:
The invention specifies precise compositional parameters for the water-soluble polymer (sulfonate group-containing monomer unit at 10-50 mass% and (meth)acrylonitrile monomer unit at 20-50 mass%). By controlling these compositional parameters, the polymer achieves optimal transition metal capturing ability while maintaining water solubility and ease of processing. The defined parameter ranges balance performance requirements with manufacturing feasibility.
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 composition effectively captures transition metal ions, enhancing the battery's cycle characteristics and heat resistance, while maintaining adhesiveness before and after electrolyte immersion, thus preventing metal deposition on the negative electrode.
Implementation Method 1
the water-soluble polymer includes a sulfonate group-containing monomer unit in a proportion of at least 10 mass% and not more than 50 mass% and a (meth)acrylonitrile monomer unit in a proportion of 20 mass% or more and 50 mass% or less... enables the capture of transition metal ions that elute from the positive electrode active material
Data Source
AI summary
Provided is a binder composition for a non-aqueous secondary battery that enables formation of a functional layer and an electrode mixed material layer having high transition metal capturing ability. The binder composition for a non-aqueous secondary battery contains a water-soluble polymer and water. The water-soluble polymer includes a sulfonate group-containing monomer unit in a proportion of at least 10 mass% and not more than 50 mass% and a (meth)acrylonitrile monomer unit in a proportion of 20 mass% or more.