Hybrid-Ether Electrolyte Composition for Lithium Dendrite Suppression
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Solution Overview
Problem
Lithium-ion batteries face limitations in energy density, safety issues due to lithium dendrite growth, thermodynamic instability, and poor cycling stability, which hinder the practical implementation of lithium-metal anodes in rechargeable batteries.
Innovation Solution
A hybrid-ether electrolyte system is developed, comprising a nonfluorinated cyclic ether and linear ether with a tailored molar ratio of salt cations to oxygen atoms, minimizing free solvent molecules and enhancing salt-solvent coordination, thereby improving cycling stability and suppressing lithium dendrite growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium-metal anodes are used to increase energy density, then capacity is improved, but uncontrollable dendrite growth causes safety issues
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by using a specific ratio of cyclic ether to linear ether (1:2 to 1:8), which modifies the solvation structure and suppresses dendrite growth while maintaining high capacity
Solution Approach 2:
The patent creates a composite electrolyte system combining cyclic ether and linear ether in specific proportions, where the cyclic ether forms protective SEI structures and the linear ether provides bulk solvation, achieving both safety and performance
2Quantity of substance
If lithium-metal anodes are used to increase capacity, then energy density is improved, but thermodynamic instability causes continuous reactions consuming lithium and electrolyte
Solution Approach 1:
The electrolyte composition is designed to preliminarily form stable protective films on the lithium surface before significant parasitic reactions occur, preventing continuous consumption of lithium and electrolyte during cycling
3Productivity
If conventional electrolytes are used with lithium-metal anodes, then initial capacity is achieved, but poor cycling stability prevents practical implementation
Solution Approach 1:
The patent optimizes the electrolyte composition parameters, specifically the cyclic to linear ether ratio and salt concentration, to simultaneously maintain high initial capacity and achieve superior cycling stability exceeding 1000 cycles
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 hybrid-ether electrolyte system significantly enhances the cycling performance and safety of lithium-metal batteries by increasing coulombic efficiency, extending cycle life, and reducing gas generation, leading to improved energy density and stability.
Implementation Method 1
a nonfluorinated hybrid-ether cosolvent system that consists of at least one nonfluorinated cyclic ether and at least one nonfluorinated linear ether, wherein the nonfluorinated hybrid-ether cosolvent system has a total number of oxygen atoms, O; and wherein the at least one salt and the nonfluorinated hybrid-ether cosolvent system are present in respective amounts such that the hybrid-ether electrolyte has an M:O molar ratio in a range of about 1:(SN−3) to about 1:(SN+3)
Data Source
AI summary
In some embodiments, hybrid-ether electrolytes that include a nonfluorinated hybrid-ether cosolvent system having at least one nonfluorinated cyclic ether and at least one nonfluorinated linear ether, wherein the number of cations, M, of an active metal (having a solvation number, SN) within the hybrid-ether electrolyte are provided in an amount such that a molar ratio between M and the number of oxygen atoms in the nonfluorinated hybrid-ether cosolvent system falls within a desired range. In some embodiments, a hybrid-ether electrolyte of this disclosure further includes at least one fluorinated ether. In some embodiments, a hybrid-ether electrolyte of this disclosure may optionally include one or more solvents differing from the solvents in the nonfluorinated hybrid-ether cosolvent system and, if provided, different from the fluorinated ether(s). Methods of making a hybrid-ether electrolyte are also disclosed, as are electrochemical cells utilizing hybrid-ether electrolytes made in accordance with the present disclosure.