Electrolyte Composition for High-Voltage Lithium-Metal Cells
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Solution Overview
Problem
Design of electrolytes for high-energy electrochemical cells is challenging due to issues such as anodic instability, corrosion of cell components, and poor transport properties, particularly in lithium-metal cells using lithium fluorosulfonyl imide (LiFSI) and dimethoxyethane (Glyme) solutions, which limit voltage stability and Coulombic efficiency.
Innovation Solution
An electrolyte composition with a balance of low-coordinating and coordinating solvents, along with high concentrations of lithium salts, is used, where the volume of the first solvent is less than or equal to the second solvent, optimizing the ratio to achieve high charge voltages, stability, and low viscosity, thereby mitigating corrosion and improving transport properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If high molarity lithium salt solutions are used to achieve high electrochemical stability, then voltage stability is improved, but electrolyte viscosity increases and transport properties deteriorate
Solution Approach 1:
The patent changes the concentration parameter of lithium salts in the electrolyte solution, using high molarity solutions (e.g., >1M, preferably >2M) to achieve high electrochemical stability while managing viscosity through solvent selection and ratio optimization
Solution Approach 2:
The patent uses composite electrolyte systems combining multiple lithium salts (e.g., LiFSI, LiPF6, LiDFOB) with various solvents (carbonates, chain ethers, cyclic ethers) to achieve both high stability and acceptable transport properties through synergistic effects
2Stability of the object's composition
If high molarity lithium salt solutions are used to achieve high electrochemical stability, then voltage stability is improved, but electrolyte cost increases
Solution Approach 1:
The patent optimizes the concentration parameter of lithium salts to achieve high voltage stability while controlling cost by selecting from multiple lithium salt options with different price points and performance characteristics
Solution Approach 2:
The patent employs multi-functional lithium salts that provide both voltage stability and corrosion protection simultaneously, reducing the need for additional expensive additives
3Stability of the object's composition
If high molarity lithium salt solutions are used to achieve high electrochemical stability, then anodic stability is improved, but Coulombic efficiency decreases
Solution Approach 1:
The patent uses composite electrolyte systems combining multiple lithium salts with different functional properties - some salts provide anodic stability while others enhance ionic conductivity and Coulombic efficiency, achieving synergistic performance
4Use of energy by moving object
If high molarity lithium salt solutions are used to achieve high electrochemical stability, then charge voltage is improved, but electrolyte density increases
Solution Approach 1:
The patent optimizes the concentration and composition parameters of the electrolyte to achieve high charge voltage while minimizing mass through selective solvent and salt combinations with favorable density characteristics
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 composition enables high-energy electrochemical cells to charge to higher voltages with improved Coulombic efficiency and stability, reducing corrosion and enhancing charge transport, while maintaining low viscosity and energy density.
Implementation Method 1
non-aqueous electrolytes that include one or more non-aqueous solvents and one or more salts
Implementation Method 2
High-molarity concentrations of these salts in solvents can coordinate a majority of solvent molecules, thus providing kinetically-stabilized solutions
Implementation Method 3
During discharge of an electrochemical cell, an oxidation-reduction reaction occurs, causing electron flow through an external circuit
Data Source
AI summary
An electrolyte, an electrochemical cell including the electrolyte, and a battery including the electrochemical cell are disclosed. Exemplary electrolytes allow for electrochemical cells and batteries with relatively high efficiency and stability that can be charged to relatively high voltages.