Electrode Sheet Interface Anchoring for All-Solid-State Battery Adhesion
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Solution Overview
Problem
All-solid state secondary batteries face challenges in achieving both high ion conductivity and excellent cycle characteristics due to increased interface resistance and inadequate adhesiveness between electrode layers and collectors, particularly in industrial manufacturing processes like roll-to-roll methods.
Innovation Solution
An electrode sheet for all-solid state secondary batteries is designed with an inorganic solid electrolyte and active material layer on a collector, featuring a polymer anchored portion with a solubility of 50% or more in water, which includes acidic functional groups, ensuring strong interlayer adhesiveness while maintaining electron conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive resin layer containing conductive fine particles is provided between the collector and the active material layer, then electron conductivity between the layers is ensured, but the interlayer adhesive force is insufficient leading to peeling off of the active material layer
Solution Approach 1:
The interface between the collector and active material layer is segmented into two distinct functional regions: a conductive fine particle-containing region for electron conductivity, and a polymer-rich region for adhesive bonding. This segmentation allows each region to optimize its specific function without compromising the other.
Solution Approach 2:
Different local regions at the interface have different compositions and properties. The conductive fine particles are localized in specific areas to provide electron conductivity, while polymer concentrates in other areas to provide adhesive force. This local quality differentiation resolves the contradiction between conductivity and adhesion.
2Reliability
If solid particles such as inorganic solid electrolyte and active material are used to form electrode layers, then high ion conductivity is achieved, but interface resistance increases due to restricted interfacial contact state
Solution Approach 1:
The polymer acts as an intermediary substance at the interface between the collector and the solid particle-based active material layer. It improves the interfacial contact state by filling gaps and creating intimate contact, thereby reducing interface resistance while maintaining the high ion conductivity of the solid particles.
Solution Approach 2:
The polymer changes the physical and chemical parameters at the interface, including surface energy, wettability, and contact area. These parameter changes enable better interfacial contact between the collector and solid particles, reducing interface resistance without affecting the ion conductivity of the solid electrolyte and active material.
3Productivity
If roll-to-roll method is used for industrial manufacturing, then productivity is improved, but adhesive force between electrode layer and collector becomes insufficient causing peeling off
Solution Approach 1:
The polymer is pre-applied to the collector surface before the active material layer is formed. This preliminary action ensures that the adhesive layer is already in place during the roll-to-roll manufacturing process, providing sufficient adhesive force to prevent peeling off even under high-speed industrial manufacturing conditions.
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 electrode sheet achieves high ion conductivity and excellent cycle characteristics by enhancing the adhesive force between the collector and electrode active material layer, reducing interface resistance, and allowing for efficient lamination in industrial applications.
Implementation Method 1
enhancing the adhesive force between the collector and electrode active material layer
Data Source
AI summary
There is provided an electrode sheet for an all-solid state secondary battery, which has an electrode active material layer containing an inorganic solid electrolyte (B) and an active material (C) on at least one surface of a collector, where the electrode sheet for an all-solid state secondary battery has an insulating polymer anchored portion that contains 50% by mass or more of a polymer (A) having a solubility of 1 g/100 g or more in water at 25° C., at a part of an interface between the collector and the electrode active material layer. There is also provided an all-solid state secondary battery in which a positive electrode or a negative electrode is composed of the electrode sheet for an all-solid state secondary battery.