Molten Salt Separator Geometry and Composite Design
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Solution Overview
Problem
Molten salt electrochemical cells, such as Sodium/sulfur (NaS) and lithium/sulfur (LiS) batteries, face issues with insulator corrosion in harsh chemical environments, leading to increased self-discharge rates due to conductive insulators, and there is a need for a different chemistry and design in energy storage devices.
Innovation Solution
A molten salt electrochemical cell design featuring a separator with specific geometries and compositions that resist mechanical damage, combined with a support structure for the cathodic material to maintain ionic communication and electrical conductivity, and a concentration gradient of cathodic material to stabilize reaction rates and extend energy storage device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ceramic tube of beta-alumina separator electrolyte is used in NaS batteries, then ionic conductivity is achieved, but mechanical strength deteriorates due to corrosion in harsh chemical environments
Solution Approach 1:
The patent employs composite materials for the separator, combining beta-alumina with other materials to form a composite structure that maintains ionic conductivity while improving mechanical strength and corrosion resistance. The composite separator integrates the electrochemical functionality of beta-alumina with the mechanical robustness of additional materials, resolving the contradiction between ionic conductivity and mechanical strength.
2Reliability
If insulators are used in molten salt batteries, then electrical insulation is provided, but self-discharge rate increases due to corrosion-induced conductivity
Solution Approach 1:
The patent addresses the corrosion issue by selecting materials that are inherently resistant to the harsh molten salt environment. Instead of trying to protect conventional insulators from corrosion, the invention uses corrosion-resistant materials from the outset, converting the harmful chemical environment into a non-degrading condition for the selected materials, thereby maintaining electrical insulation and preventing self-discharge.
3Ease of manufacture
If cathodic material is distributed uniformly in the electrochemical cell, then manufacturing simplicity is maintained, but reaction rate stability deteriorates
Solution Approach 1:
The patent implements a concentration gradient of cathodic material within the porous support structure, where the material concentration varies spatially rather than being uniform. This local variation in concentration optimizes reaction rates at different locations within the cell, improving overall reaction rate stability while utilizing the porous structure to maintain manufacturing feasibility.
4Strength
If separator thickness is increased to reduce corrosion, then mechanical strength improves, but ionic conductivity deteriorates
Solution Approach 1:
The composite separator structure allows for optimized thickness while maintaining both mechanical strength and ionic conductivity. By combining materials with complementary properties, the separator achieves the necessary mechanical robustness at reduced thickness compared to pure ceramic tubes, thereby preserving ionic conductivity pathways.
Solution Approach 2:
The patent utilizes a porous support structure that provides mechanical strength through its three-dimensional architecture rather than relying solely on material thickness. The porous structure maintains open channels for ion transport, ensuring ionic conductivity is preserved while the overall structure achieves adequate mechanical strength through its geometric design rather than increased thickness.
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 proposed design enhances the mechanical strength and ionic conductivity of the separator, reduces self-discharge rates, and maintains a stable energy storage performance by controlling the cathodic material distribution, resulting in improved energy storage efficiency and extended device lifespan.
Implementation Method 1
The first chamber is in ionic communication with the second chamber through the separator
Implementation Method 2
A cathodic material is in electrical communication with the separator and capable of forming a metal halide
Data Source
Figure 1
Figure 2A~2B
Figure 3~3J
AI summary
An article is provided. The article may include an electrochemical cell. The cell may include a molten electrolyte, and at least one molten electrode. The cell may include a structure for separating an anode from a cathode, while enabling ionic communication between the anode and cathode. An energy storage device comprising the article is also provided. Methods related to the article and the energy storage device may be provided. Separators having a cross-sectional profile normal to the axis of the cell in the shape of ellipse, triangle, rectangle, cross, star, circle, cloverleaf, square are disclosed. The separator can be domed ordimpled.The elctrodic materials can be spaced radially or axially relative to each other.