Carbonate Electrolyte with Macrocyclic Additive for Dendrite Suppression
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Solution Overview
Problem
Lithium dendrite formation and reduced cycle life in lithium metal batteries due to the charging/discharging behavior of lithium metal and carbonate-based liquid electrolytes, which limits the performance of high-energy batteries.
Innovation Solution
A carbonate-based electrolyte comprising lithium nitrate and a planar macrocyclic compound is formulated, promoting the formation of a stable artificial solid electrolyte interface (ASEI) layer by combining low concentrations of lithium nitrate and planar macrocyclic compound to enhance lithium ion conduction and inhibit dendrite growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ether-based electrolyte is used, then lithium dendrite formation is suppressed, but compatibility with high-voltage positive electrode materials is poor due to narrow electrochemical window
Solution Approach 1:
The patent uses a composite electrolyte system combining ether-based solvent (for dendrite suppression) with carbonate-based additive (for high-voltage stability). The ether component (e.g., DME, diglyme) provides lithium dendrite inhibition while the carbonate additive (e.g., EC, PC) extends the electrochemical window to accommodate high-voltage positive electrode materials, achieving both benefits simultaneously.
Solution Approach 2:
The patent modifies the electrolyte's electrochemical window parameters by introducing carbonate-based additives into the ether-based system. This changes the stability range of the electrolyte, enabling it to withstand higher voltages required for high-voltage positive electrode materials while retaining the original ether's dendrite-suppressing properties.
2Adaptability or versatility
If carbonate-based electrolyte is used, then compatibility with high-voltage positive electrode materials is improved, but lithium dendrite formation increases due to reduced solubility of lithium nitrate
Solution Approach 1:
The patent creates a composite electrolyte where ether-based solvent (excellent for dendrite suppression) is combined with carbonate-based additives (excellent for high-voltage stability). This composite approach allows the system to achieve both high-voltage compatibility and effective lithium dendrite suppression, overcoming the limitations of using either component alone.
Solution Approach 2:
The patent assigns different functional roles to different components: the ether-based solvent primarily handles lithium dendrite suppression at the negative electrode interface, while the carbonate-based additive primarily provides high-voltage stability at the positive electrode interface. This localized functional distribution resolves the contradiction between the two requirements.
3Quantity of substance
If lithium nitrate is added to carbonate electrolyte, then high-energy battery potential is achieved, but solubility of lithium nitrate is very low
Solution Approach 1:
The patent uses a composite solvent system combining ether and carbonate components. The ether portion of the composite electrolyte provides high solubility for lithium nitrate, enabling sufficient concentration of this critical additive to be achieved, while the carbonate portion maintains the high-voltage stability required for practical battery applications.
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 electrolyte stabilizes the lithium metal battery, enabling high-capacity performance and maintaining Coulombic efficiency, with minimal degradation even at high-voltage positive electrodes, and supports stable charge/discharge cycles over 25 cycles with only 1% loss.
Implementation Method 1
promote 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
Implementation Method 3
The carbonate-based electrolyte has a wider electrochemical window than the ether-based electrolyte
Data Source
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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.