Solid-State Battery Cathode Binder for Low Interfacial Resistance
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Solution Overview
Problem
Conventional lithium secondary batteries with NBR or HNBR binders face issues of high reactivity with sulfide-based compounds, leading to hardening and interfacial resistance, which affects the performance and lifespan of all-solid-state lithium-ion batteries, especially at low temperatures.
Innovation Solution
A hydrogenated acrylate-nitrile-butadiene rubber (H-ANBR) binder with controlled double bond content and composition is used, which is less reactive with sulfide-based compounds and can be completely dissolved in suitable solvents, ensuring uniform dispersion and adhesion, thereby reducing interfacial resistance and enhancing battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If NBR or HNBR binder is used in all-solid-state lithium-ion battery with sulfide-based electrolyte, then the binder can bind electrode materials, but the binder undergoes hardening due to high reactivity with sulfide-based compounds, leading to increased interfacial resistance and reduced battery performance
Solution Approach 1:
The invention changes the chemical composition parameters of the binder by introducing a specific copolymer structure with acrylonitrile (30-70 wt%) and vinylidene fluoride (30-70 wt%) units, controlling the monomer ratio to optimize the balance between adhesion strength and chemical stability with sulfide-based electrolytes
Solution Approach 2:
The invention creates a composite binder system using a copolymer of acrylonitrile and vinylidene fluoride, combining the adhesive properties of acrylonitrile with the chemical stability and electrolyte compatibility of vinylidene fluoride, achieving both strong binding and low interfacial resistance
2Stability of the object's composition
If the binder is completely dissolved in solvent for slurry preparation, then uniform dispersion is achieved, but the solvent selection becomes restricted and may affect the drying process and final electrode quality
Solution Approach 1:
The invention modifies the chemical structure parameters of the binder by incorporating vinylidene fluoride units, which introduce polar groups that enhance solubility in common solvents like NMP and DMF, thereby expanding solvent selection flexibility while maintaining uniform dispersion capability
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 use of H-ANBR binder results in improved discharging capacity and prolonged battery lifetime by minimizing hardening and maintaining interfacial resistance, ensuring stable performance across charging cycles.
Implementation Method 1
the binder is a hydrogenated acrylate-nitrile-butadiene rubber (H-ANBR) which comprises remaining double bonds in an amount of more than 0% and not more than 5.5% based on the total amount of the H-ANBR
Implementation Method 2
the binder can reduce the interfacial resistance
Data Source
AI summary
The present disclosure relates to an all-solid-state lithium-ion battery produced by applying onto a substrate a slurry in which an active material, a conductive material, a sulfide-based solid-state electrolyte, a binder and a solvent are mixed, characterized in that the binder is a hydrogenated acrylate-nitrile-butadiene rubber (H-ANBR) which comprises remaining double bonds in an amount of more than 0% and not more than 5.5% based on the total amount of the H-ANBR.