Electrode composition, electrode sheet for all-solid state secondary battery, and all-solid state secondary battery, and manufacturing methods for electrode sheet for all-solid state secondary battery and all-solid state secondary battery
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Solution Overview
Problem
Current electrode compositions for all-solid state secondary batteries face challenges in maintaining dispersion characteristics and application suitability, especially when the concentration of solid contents is increased, leading to deteriorated performance in rate characteristics and cycle characteristics.
Innovation Solution
An electrode composition comprising an inorganic solid electrolyte, an active material, a conductive auxiliary agent, and a polymer binder dissolved in a dispersion medium, where the polymer binder has specific molecular weight, polarity, and content ranges, ensuring stable dispersion and adhesion of solid particles, even at high solid content concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the concentration of solid contents is increased in the electrode composition, then the energy density and productivity are improved, but the dispersion characteristics and application suitability deteriorate
Solution Approach 1:
The patent introduces a polymer binder as an intermediary substance that mediates between the solid particles (inorganic solid electrolyte, active material, conductive auxiliary agent) and the dispersion medium. The polymer binder adsorbs onto the surfaces of solid particles through its polarity element, providing steric stabilization and preventing aggregation even at high solid content concentrations (50-90 wt%). This intermediary layer maintains dispersion characteristics while enabling high energy density.
Solution Approach 2:
The patent optimizes specific parameters of the polymer binder to resolve the contradiction: mass average molecular weight (100,000-2,000,000), polarity element value (0.5-5.0 mJ/m²), and content relative to solid particles (0.1-10 wt%). By carefully controlling these parameters, the composition achieves both high solid content concentration and stable dispersion characteristics, enabling improved energy density without sacrificing processability.
2Quantity of substance
If the concentration of solid contents is increased in the electrode composition, then the energy density is improved, but the adhesiveness and surface properties deteriorate
Solution Approach 1:
The polymer binder serves as a mediating layer between the solid particles and the current collector substrate. Its molecular structure provides both anchoring to the solid particles (through polarity element adsorption) and adhesion to the substrate, maintaining electrode integrity and electrical contact even at high solid content concentrations where particle-particle contact dominates over particle-substrate contact.
Solution Approach 2:
The patent creates a composite electrode composition combining inorganic solid particles with an organic polymer binder matrix. This composite structure leverages the high energy density of inorganic solids while the polymer matrix provides binding and adhesive functions, achieving both high concentration (50-90 wt% solids) and maintained adhesiveness through the synergistic combination of materials.
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 composition achieves excellent dispersion characteristics, adhesiveness, and surface properties, enhancing the rate characteristics of all-solid state secondary batteries by stabilizing the dispersion and adhesion of solid particles, even at high solid content concentrations.
Implementation Method 1
a polymer binder (B), and a dispersion medium (D), wherein the polymer binder (B) includes a polymer binder (B1) that is dissolved in the dispersion medium (D)
Implementation Method 2
the polymer binder (B1), the inorganic solid electrolyte (SE), the active material (AC), and the conductive auxiliary agent (CA) satisfy the following conditions (1) to (4)... a value of a polarity element of surface energy of the polymer constituting the polymer binder (B1) is 0.5 mJ/m2 or more
Data Source
AI summary
There is provided an electrode composition containing an inorganic solid electrolyte (SE), an active material (AC), a conductive auxiliary agent (CA), a polymer binder (B), and a dispersion medium (D), where the polymer binder (B) being includes a polymer binder (B1) that is dissolved in the dispersion medium (D) and the electrode composition satisfies specific conditions (1) to (4), and there are provided an electrode sheet for an all-solid state secondary battery and an all-solid state secondary battery, and manufacturing methods for an electrode sheet for an all-solid state secondary battery and an all-solid state secondary battery, in which the electrode composition is used.