Binder Composition for Non-Aqueous Battery SEI Film Formation
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Solution Overview
Problem
Conventional binder compositions for non-aqueous secondary batteries fail to form a good Solid Electrolyte Interphase (SEI) film at low-temperature and low-depth of charge conditions, limiting the improvement of battery life characteristics.
Innovation Solution
A binder composition for non-aqueous secondary battery positive electrodes containing iron and at least one of ruthenium and rhodium, with total iron, ruthenium, and rhodium content limited to no greater than 5×10^-3 parts by mass per 100 parts by mass of the binder, combined with a fluorine-containing polymer, promotes SEI film formation and enhances battery life characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional binder compositions are used, then manufacturing cost is reduced, but SEI film formation capability at low-temperature and low-depth of charge conditions deteriorates
Solution Approach 1:
The invention changes the chemical composition parameters of the binder by incorporating specific metal elements (Fe, Ru, Rh) at controlled concentrations. This compositional modification enables the binder to catalyze SEI film formation under low-temperature and low-depth of charge conditions, resolving the contradiction between maintaining low manufacturing cost and achieving reliable SEI film formation capability.
Solution Approach 2:
The metal elements (Fe, Ru, Rh) act as intermediaries or catalysts that facilitate SEI film formation. These intermediaries enable the electrochemical reactions necessary for SEI formation to proceed effectively under otherwise insufficient conditions (low temperature and low depth of charge), thereby improving reliability without requiring expensive manufacturing processes.
2Productivity
If aging treatment is performed at low-temperature and low-depth of charge, then productivity is improved, but SEI film formation quality deteriorates
Solution Approach 1:
The invention modifies the binder composition parameters to include specific metal catalysts that lower the activation energy for SEI film formation. This enables the aging process to be conducted at lower temperatures and lower depths of charge while still achieving high-quality SEI films, thereby improving productivity without sacrificing film quality.
Solution Approach 2:
The metal elements in the binder serve as intermediaries that facilitate the electrochemical reactions during aging treatment. They enable SEI film formation to proceed efficiently under milder aging conditions, allowing for faster, lower-cost aging processes that maintain or improve SEI film quality.
3Reliability
If total iron, ruthenium, and rhodium content is increased, then SEI film formation capability is improved, but binder composition complexity increases
Solution Approach 1:
The invention optimizes the concentration parameters of metal elements in the binder, specifying that Fe, Ru, and Rh are each present at 0.01-5 mass%. This controlled parameter range achieves effective SEI film formation while preventing excessive complexity in the binder composition, balancing performance with compositional simplicity.
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 proposed binder composition enables the formation of a non-aqueous secondary battery with excellent life characteristics even under low-temperature and low-depth of charge conditions, improving ion conductivity and reducing internal resistance.
Implementation Method 1
form a solid electrolyte interphase (SEI) film at the surface of an electrode active material
Data Source
AI summary
Provided is a binder composition for a non-aqueous secondary battery positive electrode that can form a positive electrode with which it is possible to obtain a non-aqueous secondary battery having excellent life characteristics even when aging treatment is carried out under low-temperature and low-depth of charge conditions. The binder composition contains a first binder, iron, and at least one of ruthenium and rhodium. The total iron, ruthenium, and rhodium content is no greater than 5×10-3 parts by mass per 100 parts by mass of the first binder.