Solid Electrolyte Buffer Region Directing Metal Deposition
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Solution Overview
Problem
Current solid-state electrolytes in batteries with metal negative electrodes face issues such as internal shorts due to metal deposition across the separator, leading to performance loss and safety concerns, as the ionic conductivity of the electrolyte is often less than the electronic conductivity of the metal, causing mechanical stress and fatigue in the separator.
Innovation Solution
A solid electrolyte design featuring a first porous solid electrolyte with a coating that is less favorable for metal deposition, an adhesive electrolyte layer, and a second porous solid electrolyte with a surface more favorable for deposition, creating a buffer region between the metal electrode and the separator to direct metal deposition away from the separator, thereby reducing stress and preventing internal shorts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid electrolyte is used in a battery with a metal negative electrode, then safety is improved compared to liquid electrolytes, but internal shorts occur due to metal deposition penetrating across the separator
Solution Approach 1:
The electrolyte is designed with different regions having distinct properties: a first region with an ionic conductivity to electronic conductivity ratio of at least 1:1 (preferably at least 10:1, more preferably at least 100:1) and a second region with different deposition characteristics. This local differentiation prevents metal deposition in the separator region while maintaining overall battery safety and function.
Solution Approach 2:
The electrolyte is divided into multiple distinct regions with different functional properties. The first region is optimized for preventing metal deposition and internal shorts, while the second region maintains overall ionic conductivity. This segmentation allows each region to perform its specific function without interfering with the other.
2Quantity of substance
If the ionic conductivity of the electrolyte is less than the electronic conductivity of the metal, then metal deposition occurs, but this causes mechanical stress and fatigue in the separator
Solution Approach 1:
The electrolyte's first region is specifically engineered with high ionic conductivity relative to electronic conductivity (ratio of at least 1:1, preferably at least 10:1, more preferably at least 100:1). This local property ensures that metal ions are transported ionically rather than electronically, preventing metal deposition and the associated mechanical stress and fatigue in the separator.
3Ease of manufacture
If a uniform electrolyte structure is used, then manufacturing is simplified, but metal deposition occurs across the entire electrolyte surface including near the separator
Solution Approach 1:
The electrolyte is designed with spatially varying properties: the first region has specific ionic-to-electronic conductivity ratios to prevent metal deposition, while the second region has different characteristics. This local differentiation targets metal deposition prevention specifically where needed (near the separator) without requiring complete redesign of the entire electrolyte structure.
Solution Approach 2:
The electrolyte is segmented into functional regions that can be manufactured and assembled separately. The first region with optimized conductivity ratios can be prepared and then combined with the second region, allowing for modular manufacturing that addresses the metal deposition problem while maintaining manufacturing feasibility.
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 design effectively prevents internal shorts by directing metal deposition towards the current collector, reducing mechanical stress on the separator and enhancing the robustness and safety of the battery, while allowing for separate fabrication and adherence of the electrolyte layers for improved manufacturing efficiency.
Implementation Method 1
a first coating on the first surface of the first porous solid electrolyte... wherein a surface of the first coating is less favorable for deposition of the deposition metal than the second surface of the second solid electrolyte
Implementation Method 2
an adhesive electrolyte layer on the first porous solid electrolyte... a second porous solid electrolyte on the adhesive electrolyte layer
Implementation Method 3
the first porous solid electrolyte and the second porous solid electrolyte each have an ionic conductivity effective for a deposition metal
Data Source
AI summary
A solid electrolyte for a negative electrode of a secondary battery includes a first porous solid electrolyte having a first surface; a first coating on the first surface of the first porous solid electrolyte; an adhesive electrolyte layer on the first porous solid electrolyte; and a second porous solid electrolyte on the adhesive electrolyte layer, the second porous solid electrolyte having a second surface; wherein the first porous solid electrolyte and the second porous solid electrolyte each have an ionic conductivity effective for a deposition metal; and wherein a surface of the first coating is less favorable for deposition of the deposition metal than the second surface of the second solid electrolyte. An electrode assembly and an electrochemical cell including the solid electrolyte and method for the manufacture thereof are also described.