Lithium-Chalcogen Battery Electrolyte System Design
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Solution Overview
Problem
Conventional lithium-chalcogen rechargeable batteries, such as lithium-sulfur and lithium-selenium batteries, face limitations in energy density and redox reactions due to the use of lithium nitrate, which decomposes and results in energy loss, and are restricted to ether-based solvents, limiting their performance.
Innovation Solution
The development of an electrochemical cell with an electrolyte system comprising specific lithium salts like lithium bis(fluorosulfonyl)imide and solvents like cyclic carbonates, linear carbonates, and ethers, excluding lithium nitrate, to achieve improved energy density and stable cycling performance, with a minimum charge potential of 0.8 V to 1.8 V and a maximum charge potential of 2.5 V to 3 V.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium nitrate is used in the electrolyte, then successful cycling of the electrochemical cell is induced, but the battery has a minimum voltage of about 1.8 V resulting in about 15% energy loss
Solution Approach 1:
The patent removes lithium nitrate from the electrolyte composition entirely, replacing it with alternative lithium salts (lithium halides, lithium carboxylates, lithium sulfonates) that enable successful cycling without imposing the 1.8 V minimum voltage constraint, thereby eliminating the associated energy loss
Solution Approach 2:
The patent changes the chemical composition parameters of the electrolyte by substituting lithium nitrate with other lithium salt compounds having different electrochemical properties, specifically those that do not decompose at low voltages, enabling operation below 1.8 V while maintaining cycling reliability
2Reliability
If ether-based solvents are used in the electrolyte, then the battery can operate, but the electrolyte system is limited and cannot use carbonate-based electrolytes due to negative effects of active radical chalcogens
Solution Approach 1:
The patent develops an electrolyte system using lithium halide salts (particularly lithium iodide and lithium bromide) that are universally compatible with both ether-based and carbonate-based solvents, eliminating the restriction to only ether-based systems and enabling versatile solvent selection based on performance requirements
Solution Approach 2:
The patent introduces lithium halide salts as intermediary compounds that mediate between the chalcogen-containing electroactive material and the solvent system, preventing direct harmful interactions between active radical chalcogens and carbonate-based solvents while enabling successful electrochemical cycling
3Reliability
If conventional electrolyte systems are used, then the battery can cycle, but the energy density is limited due to the 1.8 V minimum voltage constraint
Solution Approach 1:
The patent converts the previously harmful low-voltage operation (which caused lithium nitrate decomposition) into a beneficial feature by using alternative electrolyte compositions that are stable at low voltages, thereby enabling full utilization of the electrochemical potential difference and achieving higher energy density while maintaining cycling capability
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
This configuration enhances energy density and reduces Coulombic capacity loss, maintaining performance over multiple cycles without the need for lithium nitrate, allowing for efficient lithium ion cycling with improved redox reactions and capacity retention.
Implementation Method 1
The electrolyte is suitable for conducting lithium-ions
Implementation Method 2
cathode materials for lithium-ion batteries typically comprise an electroactive material which can be intercalated or alloyed with lithium ions
Implementation Method 3
cathode materials for lithium-ion batteries typically comprise an electroactive material which can be intercalated or alloyed with lithium ions
Implementation Method 4
Lithium-ions move from a cathode (positive electrode) to an anode (negative electrode) during charging of the battery, and in the opposite direction when discharging the battery
Implementation Method 5
The electrolyte typically contains one or more lithium salts which may be dissolved and ionized in a non-aqueous solvent
Implementation Method 6
The electrolyte typically contains one or more lithium salts which may be dissolved and ionized in a non-aqueous solvent
Data Source
AI summary
An electrolyte system for an electrochemical cell having an electrode comprising a chalcogen-containing electroactive material is provided, along with methods of making the electrolyte system. The electrolyte system includes one or more lithium salts dissolved in one or more solvents. The salts have a concentration in the electrolyte of greater than or equal to about 2M to less than or equal to about 5M. The electrochemical cell including the electrolyte system has a minimum potential greater than or equal to about 0.8 V to less than or equal to about 1.8 V and a maximum charge potential of greater than or equal to about 2.5 V to less than or equal to about 3 V.