Carbonate-Ether Electrolyte for Dendrite-Stable Lithium Metal Batteries
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Solution Overview
Problem
Lithium metal batteries face issues with lithium dendrite formation and reduced cycle life due to the charging/discharging behavior in liquid electrolytes, and conventional ether-based electrolytes have limitations with high-voltage positive electrode materials.
Innovation Solution
A carbonate-based electrolyte is developed, comprising a mixture of carbonate, ether, lithium nitrate, and a planar macrocyclic compound, with specific weight ratios and concentrations, which promotes the formation of a stable solid electrolyte interface (SEI) layer, enabling better ion conduction and inhibiting lithium dendrite growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ether-based electrolyte is used, then lithium dendrite growth is inhibited, but high-voltage positive electrode materials cannot be used due to narrow electrochemical window
Solution Approach 1:
The patent combines ether-based electrolyte and carbonate-based electrolyte in a specific volume ratio (1:1 to 1:4) to create a hybrid electrolyte system. This merging allows the electrolyte to simultaneously provide lithium dendrite inhibition (from ether component) and compatibility with high-voltage positive electrode materials (from carbonate component), resolving the contradiction between these two requirements.
Solution Approach 2:
The electrolyte uses a composite formulation combining ether solvents (such as dimethoxymethane, diethylene glycol dimethyl ether) and carbonate solvents (such as ethylene carbonate, dimethyl carbonate) with specific volume ratios. This composite electrolyte composition enables both lithium dendrite suppression and high-voltage stability, allowing the system to achieve properties that neither component could provide alone.
2Adaptability or versatility
If carbonate-based electrolyte is used, then high-voltage positive electrode material can be used, but lithium dendrite formation occurs and cycle life is reduced
Solution Approach 1:
The patent combines ether-based electrolyte and carbonate-based electrolyte in a specific volume ratio (1:1 to 1:4) to create a hybrid electrolyte system. This merging allows the electrolyte to simultaneously provide lithium dendrite inhibition (from ether component) and compatibility with high-voltage positive electrode materials (from carbonate component), resolving the contradiction between these two requirements.
Solution Approach 2:
The electrolyte uses a composite formulation combining ether solvents (such as dimethoxymethane, diethylene glycol dimethyl ether) and carbonate solvents (such as ethylene carbonate, dimethyl carbonate) with specific volume ratios. This composite electrolyte composition enables both lithium dendrite suppression and high-voltage stability, allowing the system to achieve properties that neither component could provide alone.
3Reliability
If lithium nitrate is added to carbonate electrolyte, then SEI layer formation is promoted and ion conduction is improved, but solubility of lithium nitrate is very low
Solution Approach 1:
The patent combines ether-based electrolyte and carbonate-based electrolyte in a specific volume ratio (1:1 to 1:4) to create a hybrid electrolyte system. This merging allows the electrolyte to simultaneously provide lithium dendrite inhibition (from ether component) and compatibility with high-voltage positive electrode materials (from carbonate component), resolving the contradiction between these two requirements.
Solution Approach 2:
The patent changes the solvent composition parameters by introducing ether components with specific dielectric constants and donor numbers, which alter the solvation environment for lithium nitrate. This parameter change increases the solubility of lithium nitrate in the electrolyte while maintaining its ability to form stable SEI layers and enable high-voltage operation.
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 carbonate-based electrolyte enhances the stability and cycle life of lithium metal batteries, allowing them to operate with high-voltage positive electrodes while maintaining high Coulombic efficiency and specific capacity, with minimal degradation over multiple charge/discharge cycles.
Implementation Method 1
promotes the formation of an inorganic solid electrolyte interface (SEI) layer by adding an additive to the electrolyte
Implementation Method 2
accelerate the conduction of the lithium ion between interfaces
Data Source
AI summary
The present application provides a carbonate-based electrolyte. The carbonate-based electrolyte includes a carbonate, an ether, a lithium salt, a lithium nitrate, and a planar macrocyclic compound. The present application further provides a method for making the carbonate-based electrolyte and a lithium metal battery using the carbonate-based electrolyte.