Layered Solid Electrolyte Structure for All-Solid-State Battery Capacity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
All-solid secondary batteries face issues with low reversible capacity and frequent short circuits due to inadequate interfacial characteristics between the cathode layer and the solid electrolyte layer, particularly when using sulfide-based electrolytes.
Innovation Solution
The battery design incorporates a bimodal cathode active material with large and small-diameter particles, along with a layered solid electrolyte structure comprising a first solid electrolyte layer adjacent to the cathode and a second solid electrolyte layer adjacent to the anode, where the second electrolyte has higher ion conductivity and larger size than the first, enhancing ion mobility and contact area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-layer solid electrolyte structure is used, then the device complexity is reduced, but the ion conductivity and contact area are insufficient leading to low reversible capacity
Solution Approach 1:
The solid electrolyte layer is segmented into two distinct layers: a first solid electrolyte layer adjacent to the cathode containing smaller particles, and a second solid electrolyte layer adjacent to the anode containing larger particles with higher ion conductivity. This segmentation allows each layer to perform its specific function optimally, resolving the contradiction between maintaining simple structure and achieving high reversible capacity.
Solution Approach 2:
Different regions of the solid electrolyte layer are assigned different properties: the first layer near the cathode uses smaller particles for better contact area, while the second layer near the anode uses larger particles for higher ion conductivity. This local differentiation of material properties enables the system to achieve high reversible capacity without excessive overall complexity.
2Reliability
If only small-particle solid electrolyte is used, then the contact area with electrodes is increased, but the ion conductivity is reduced leading to low reversible capacity at high rate
Solution Approach 1:
The electrolyte system is divided into two segments with different particle sizes: small particles in the first layer for contact area, and large particles in the second layer for ion conductivity. This segmentation resolves the contradiction by distributing the conflicting requirements to different spatial locations.
Solution Approach 2:
The patent applies local quality by assigning small particle size to the cathode-adjacent layer where contact area is critical, and large particle size to the anode-adjacent layer where ion conductivity is paramount. This localized optimization enables high-rate performance while maintaining sufficient ion conductivity.
3Reliability
If a simple single-layer electrolyte structure is used, then the manufacturing process is simplified, but short circuits occur frequently during repetitive charging and discharging
Solution Approach 1:
The electrolyte is segmented into two layers with different particle sizes optimized for their respective positions, which prevents short circuits during cycling by ensuring both good contact and high ion conductivity. The manufacturing process remains relatively simple by using sequential deposition or blending approaches.
Solution Approach 2:
The patent employs a composite electrolyte structure combining two types of solid electrolyte particles with different size distributions. This composite approach enhances cycle stability by preventing short circuits while maintaining a manufacturable process through conventional mixing and deposition techniques.
4Quantity of substance
If larger particle size solid electrolyte is used, then the ion conductivity is improved, but the contact area with electrodes is reduced
Solution Approach 1:
The electrolyte system is segmented spatially: large particles are placed in the second layer where ion conductivity is the primary requirement, while small particles are placed in the first layer where contact area is critical. This segmentation resolves the contradiction by decoupling the two competing requirements into different spatial zones.
Solution Approach 2:
The patent implements local quality by varying particle size based on location: small particles near the cathode maximize contact area, while large particles near the anode maximize ion conductivity. This localized property differentiation enables the system to achieve both high ion conductivity and sufficient contact area.
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 improves high-rate performance and energy density by optimizing ion conductivity and contact area, reducing the likelihood of short circuits and enhancing charge/discharge capacity.
Implementation Method 1
the second solid electrolyte has a larger size than the solid electrolyte of the cathode layer or the first solid electrolyte, and the second solid electrolyte has higher ion conductivity than the first solid electrolyte
Data Source
AI summary
Provided are an all-solid secondary battery and a method of manufacturing the same, the all-solid secondary battery including: an anode layer; a cathode layer; and a solid electrolyte layer between the anode layer and the cathode layer, wherein the cathode layer contains a large-particle cathode active material, a small-diameter cathode active material, and a solid electrolyte, the solid electrolyte layer includes a first solid electrolyte layer adjacent to the cathode layer and containing a first solid electrolyte, and a second solid electrolyte layer adjacent to the anode layer and containing a second electrolyte, the second solid electrolyte has a larger size than the solid electrolyte of the cathode layer or the first solid electrolyte, and the second solid electrolyte has higher ion conductivity than the first solid electrolyte.