Electrolyte Composition for Lithium-Ion Battery Performance
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Solution Overview
Problem
Existing electrochemical devices, such as lithium-ion batteries, face performance issues due to the dissolution and deposition of metal elements in the positive active material, affecting rate performance, low-temperature discharge, and high-temperature storage and cycle performance, which is exacerbated by the high viscosity and low dielectric constant of solvents like diethyl carbonate.
Innovation Solution
An electrolyte composition comprising dimethyl carbonate, ethyl methyl carbonate, and lithium bis(oxalato)borate, optimized within specific weight percentage ranges, along with additional components like ethylene carbonate, 1,3-propane sultone, and vinylene carbonate, to enhance infiltration and form stable solid electrolyte interfaces, reducing metal element dissolution and deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the areal density and compacted density of the coating layer are increased to reduce auxiliary materials and improve energy density, then the energy density of the battery is improved, but the infiltration capabilities and kinetic performance of the electrolyte deteriorate
Solution Approach 1:
The patent modifies the chemical composition parameters of the electrolyte by incorporating specific additives (lithium bis(oxalato)borate at 0.05-1.0 wt%, 1,3-propane sultone at 0.1-5.0 wt%, vinylene carbonate at 0.1-2.0 wt%) into the carbonate solvent system. These parameter changes enable the electrolyte to effectively infiltrate high-density coating layers while maintaining good kinetic performance, thus resolving the contradiction between improved energy density and deteriorated infiltration capability
Solution Approach 2:
The patent creates a composite electrolyte system by combining multiple components: cyclic carbonates (EC, PC), chain carbonates (DMC, DEC, EMC), and functional additives (LiBOB, 1,3-PS, VC). This composite formulation synergistically improves both infiltration capability and kinetic performance, allowing the electrolyte to effectively penetrate high-density coating layers while maintaining excellent electrochemical performance
2Reliability
If solvents like diethyl carbonate are used, then the electrolyte has certain solvating ability, but the high viscosity and low dielectric constant reduce infiltration and kinetic performance
Solution Approach 1:
The patent formulates a composite electrolyte combining cyclic carbonates (EC, PC) with chain carbonates (DMC, DEC, EMC) in optimized proportions. This composite system balances the high dielectric constant and solvating ability of cyclic carbonates with the low viscosity and high ionic conductivity of chain carbonates, achieving both reliable solvating ability and excellent kinetic performance
Solution Approach 2:
The patent optimizes the ratio parameters between different carbonate solvents and introduces functional additives to modify the electrolyte's physical and chemical parameters. By adjusting the composition ratios and adding LiBOB, 1,3-PS, and VC, the electrolyte achieves optimal viscosity and dielectric constant balance, improving kinetic performance while maintaining solvating ability
3Power
If metal elements in the positive active material dissolve and deposit, then the electrochemical device shows certain electrochemical activity, but the rate performance, low-temperature discharge, and high-temperature storage and cycle performance deteriorate
Solution Approach 1:
The patent introduces lithium bis(oxalato)borate (LiBOB) as an intermediary substance that forms protective interface films on electrode surfaces. This intermediary layer prevents direct contact between the electrolyte and metal elements in the positive active material, suppressing dissolution and deposition reactions. The result is improved high-temperature storage performance and cycle stability while maintaining electrochemical activity
Solution Approach 2:
The patent modifies the electrolyte's chemical composition by adding specific concentrations of LiBOB (0.05-1.0 wt%), 1,3-propane sultone (0.1-5.0 wt%), and vinylene carbonate (0.1-2.0 wt%). These parameter changes optimize the formation of protective interface films, effectively suppressing metal element dissolution and deposition, thereby improving reliability including high-temperature storage and cycle performance
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 optimized electrolyte achieves balanced high-temperature storage, high-temperature cycle, rate, and low-temperature discharge performance by controlling the weight percentages of its components, resulting in improved comprehensive performance of electrochemical devices.
Implementation Method 1
form stable solid electrolyte interfaces, reducing metal element dissolution and deposition
Implementation Method 2
higher requirements are imposed on the infiltration capabilities and kinetic performance of the electrolyte
Data Source
AI summary
An electrolyte, an electrochemical device containing same, and an electronic device. Specifically, an electrolyte, including dimethyl carbonate, ethyl methyl carbonate, and lithium bis(oxalato)borate. The ethyl methyl carbonate and the lithium bis(oxalato)borate each account for a specified weight percent in the electrolyte, and the weight percent of the dimethyl carbonate and the weight percent of the ethyl methyl carbonate in the electrolyte meet a specified relationship. The electrolyte according to this application helps to balance the rate performance, the low-temperature discharge performance, and the high-temperature storage and cycle performance of the electrochemical device, and helps to achieve excellent comprehensive performance of the electrochemical device.