All-solid battery anode binder for low interfacial resistance
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Solution Overview
Problem
All-solid secondary batteries manufactured using a warm isostatic press method exhibit poor performance due to decreased binding strength between electrode layers, and increasing the amount of polyvinylidene fluoride binder leads to increased interfacial resistance, reducing capacity and overall battery performance.
Innovation Solution
Incorporating a polyvinyl alcohol-based copolymer as a binder in the anode active material layer, which improves the binding strength and flexibility of the anode active material layer, and reduces interfacial resistance between the anode and solid electrolyte layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the amount of polyvinylidene fluoride binder is increased to improve binding strength, then binding strength between electrode layers is improved, but interfacial resistance between electrode layer and solid electrolyte layer increases
Solution Approach 1:
The patent changes the chemical composition parameters of the binder from polyvinylidene fluoride to polyvinyl alcohol-based copolymer, which has different physical and chemical properties. This parameter change allows achieving both high binding strength and low interfacial resistance simultaneously, as the polyvinyl alcohol-based copolymer provides adequate adhesion while maintaining good interfacial contact with solid electrolyte layers.
Solution Approach 2:
The patent uses a composite binder system comprising polyvinyl alcohol as the main chain and various copolymer units (acrylic acid, fumaric acid, maleic acid, itaconic acid, and their esters or amides) as side chains. This composite structure combines the adhesive properties of polyvinyl alcohol with the functional groups from copolymer units, achieving both strong binding and low interfacial resistance through synergistic effects of different material components.
2Quantity of substance
If conventional electrode layers are pressed using warm isostatic press to manufacture large-capacity battery, then battery capacity is increased, but binding strength of electrode layers decreases
Solution Approach 1:
The patent changes the binder material parameter from polyvinylidene fluoride to polyvinyl alcohol-based copolymer, which maintains superior binding strength even after warm isostatic pressing. The polyvinyl alcohol-based copolymer's molecular structure and adhesive properties are more resistant to degradation under pressing conditions, allowing large-capacity batteries to be manufactured without sacrificing electrode layer binding strength.
Data Source
AI summary
An all-solid secondary battery including: a cathode; an anode; and a solid electrolyte layer interposed between the cathode and the anode, wherein the cathode includes a cathode active material, wherein the anode includes an anode current collector and an anode active material layer on the anode current collector, wherein the anode active material layer includes a binder and an anode active material that does not include an alkali metal, wherein the binder includes a polymer main chain and a polyvinyl alcohol-containing copolymer, and wherein the polymer main chain includes polyvinyl alcohol, a polyvinyl alcohol derivative, or a combination thereof, and the polyvinyl alcohol-containing copolymer has at least one repeating unit linked to the polymer main chain.