All-solid-state battery positive electrode segmentation
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Solution Overview
Problem
Current all-solid-state batteries face challenges in maximizing battery capacity due to disorderly mixing of positive electrode active material, solid electrolyte, and conductive fibers, which inhibits lithium ion conduction and deteriorates dispersibility, leading to decreased battery performance.
Innovation Solution
The battery design incorporates a positive electrode layer with a fiber-containing region and a fiber-free region, where the conductive fibers are concentrated between positive electrode active materials to form a conductive path, and the fiber-free region ensures unobstructed ion conduction, utilizing a unified solid electrolyte material and a specific ratio of active material to electrolyte to enhance both ion and electron conduction paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conductive fibers are mixed disorderly with positive electrode active material and solid electrolyte, then the electrode structure is simple to manufacture, but lithium ion conduction is inhibited and battery performance deteriorates
Solution Approach 1:
The positive electrode layer is segmented into fiber-containing regions and fiber-free regions. Conductive fibers are concentrated in specific regions rather than being uniformly distributed, creating distinct functional zones that facilitate both electron conduction and ion conduction without mutual interference.
Solution Approach 2:
Different regions of the positive electrode layer have different properties: fiber-containing regions provide electron conduction pathways, while fiber-free regions provide unobstructed lithium ion conduction pathways. This local differentiation optimizes both conduction functions simultaneously.
2Reliability
If conductive fibers are distributed throughout the positive electrode layer, then electron conduction is improved, but lithium ion conduction is obstructed and battery capacity decreases
Solution Approach 1:
The positive electrode layer is divided into fiber-containing regions for electron conduction and fiber-free regions for ion conduction. This segmentation allows electron conduction to be improved through fiber distribution while preventing ion conduction obstruction by restricting fibers to specific regions.
Solution Approach 2:
The fiber-containing region acts as an intermediary structure that provides electron conduction pathways without directly blocking ion conduction pathways. The spatial separation creates independent channels for electrons and ions to move without interference.
3Ease of manufacture
If solid electrolyte and conductive fibers are mixed uniformly, then manufacturing process is simplified, but dispersibility deteriorates and battery performance decreases
Solution Approach 1:
Instead of uniform mixing, the electrode is structured with segmented regions containing different material concentrations. This approach maintains manufacturing simplicity while achieving superior dispersibility through controlled spatial distribution rather than homogeneous mixing.
Solution Approach 2:
The electrode structure implements local quality variations where fiber concentration differs between regions. This creates optimal local environments for both electron conduction and ion conduction, improving overall material dispersibility and battery performance.
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
This configuration effectively secures stable ion and electron conduction paths, improving battery capacity and charge-discharge efficiency, particularly under high-rate discharge conditions, while minimizing solvent content to prevent material deterioration.
Implementation Method 1
a solid electrolyte or an electrolyte solution obtained by dissolving a supporting salt such as lithium hexafluorophosphate in an organic solvent is used for the electrolyte... using a noncombustible solid electrolyte as the electrolyte... Lithium ion conductivities of these solid electrolytes are about 10−4 S/cm to 10−3 S/cm
Implementation Method 2
a positive electrode layer containing a positive electrode active material, a first solid electrolyte, a second solid electrolyte, and a conductive fiber... a fiber-containing region that coats the positive electrode active material and that contains the conductive fiber and the first solid electrolyte
Data Source
AI summary
An all-solid-state battery has a structure including a positive electrode current collector; a positive electrode layer containing a positive electrode active material, a first solid electrolyte, a second solid electrolyte, and a conductive fiber; a solid electrolyte layer containing a fourth solid electrolyte; a negative electrode layer containing a negative electrode active material and a third solid electrolyte; and a negative electrode current collector. These are stacked in this order. The positive electrode layer includes: a fiber-containing region that coats the positive electrode active material and that contains the conductive fiber and the first solid electrolyte; and a fiber-free region that is located in a gap surrounded by the positive electrode active material coated by the fiber-containing region. The fiber-free region is free of the conductive fiber, and contains the second solid electrolyte.