Siloxane Battery Electrolytes to Suppress Polysulfide Dissolution
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Solution Overview
Problem
Rechargeable batteries with selenium or sulfur cathodes face degradation due to the dissolution of polysulfides and polyselenides, leading to reduced performance and susceptibility to failure, as existing technologies fail to effectively suppress their dissolution in the electrolyte.
Innovation Solution
Incorporating a high concentration of a salt in a poly(alkylene oxide) siloxane electrolyte, ranging from 2 M to 10 M, to prevent the dissolution of polysulfides and polyselenides, thereby stabilizing the electrochemical device and enhancing its performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolytes are used in rechargeable batteries with selenium or sulfur cathodes, then the batteries can operate, but the polysulfides and polyselenides dissolve in the electrolyte leading to performance degradation and reduced reliability
Solution Approach 1:
The patent changes the concentration parameter of the electrolyte by using high concentration poly(alkylene oxide) siloxane electrolytes with specific molecular weights and concentrations, which fundamentally alters the solvation environment to suppress polysulfides/polyselenides dissolution while maintaining electrochemical performance
Solution Approach 2:
The patent employs composite electrolyte systems combining poly(alkylene oxide) siloxanes with specific salts (LiTFSI, NaTFSI) and co-solvents (carbonates, ethers) to create a multi-component system that simultaneously prevents dissolution and enables efficient ion transport
2Reliability
If high concentration poly(alkylene oxide) siloxane electrolytes are used, then the dissolution of polysulfides and polyselenides is suppressed improving reliability, but the electrolyte formulation becomes more complex
Solution Approach 1:
The patent systematically optimizes key parameters including poly(alkylene oxide) siloxane molecular weight (500-5000 g/mol), salt concentration (2-10 M), and co-solvent ratios to achieve the optimal balance between dissolution suppression and electrochemical performance, reducing formulation complexity through defined parameter ranges
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 high salt concentration in the poly(alkylene oxide) siloxane electrolyte significantly suppresses the interaction between polysulfides/polyselenides and the electrolyte, leading to improved cycle stability and performance, with increased reversible capacity and coulombic efficiency in lithium and sodium batteries.
Implementation Method 1
Incorporating a high concentration of a salt in a poly(alkylene oxide) siloxane electrolyte, ranging from 2 M to 10 M, to prevent the dissolution of polysulfides and polyselenides
Data Source
AI summary
An electrochemical device includes a cathode including elemental selenium, elemental sulfur, or selenium-sulfur containing composite; a negative electrode; a separator; and an electrolyte including a poly(alkyleneoxide) siloxane; and a salt; wherein a concentration of the salt in the electrolyte is sufficient to minimize dissolution of polysulfides/polyselenides formed during cycling of the device.