Lithium Ion Battery Electrolyte for High Voltage Stability
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Solution Overview
Problem
Lithium ion secondary batteries with 5 V-class positive electrodes face challenges in maintaining high cycle characteristics at room temperature while suppressing gas generation at high temperatures, due to issues with electrolyte degradation and ionic conductance.
Innovation Solution
A lithium ion secondary battery design incorporating a non-aqueous electrolyte solution with a fluorinated phosphate ester and a sulfone compound, where the sulfone compound is included in an amount of 5 volume % or higher, to improve oxidation resistance and ionic conductance, thereby enhancing cycle characteristics and reducing gas generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a 5 V-class positive electrode active material is used to increase operating voltage and energy density, then energy density is improved, but gas generation increases and cycle characteristics deteriorate at high temperatures
Solution Approach 1:
The patent introduces a specific electrolyte solution composition as an intermediary between the 5V positive electrode and the battery system. The electrolyte contains a fluorinated cyclic carbonate (10-30 vol%), a chain carbonate (70-85 vol%), and a cyclic carboxylate (5-20 vol%), which mediates the interaction by suppressing oxidative degradation and preventing gas generation while maintaining high voltage operation and energy density.
2Power
If the positive electrode operating potential is increased to 4.5 V or higher, then voltage and energy density are improved, but oxidative degradation of the electrolyte solution occurs
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte solution by incorporating specific additives: fluorinated cyclic carbonate (10-30 vol%), chain carbonate (70-85 vol%), and cyclic carboxylate (5-20 vol%). This parameter change increases the oxidation resistance of the electrolyte, enabling stable operation at 4.5V or higher while maintaining reliability.
3Power
If conventional electrolyte solutions are used with 5 V-class positive electrodes, then high voltage operation is achieved, but cycle characteristics deteriorate at room temperature
Solution Approach 1:
The patent creates a composite electrolyte solution by combining three different types of solvents in specific proportions: fluorinated cyclic carbonate (10-30 vol%), chain carbonate (70-85 vol%), and cyclic carboxylate (5-20 vol%). This composite formulation provides both high voltage stability and excellent cycle characteristics at room temperature, resolving the contradiction between power and duration.
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 battery achieves improved cycle characteristics at room temperature and reduced gas generation at high temperatures, maintaining high capacity retention ratios through the balanced properties of the electrolyte solution.
Implementation Method 1
use of a solvent with a high oxidation resistance can be employed... a fluorinated phosphate ester... and at least one selected from the group consisting of a sulfone compound
Implementation Method 2
improve oxidation resistance and ionic conductance, thereby enhancing cycle characteristics
Data Source
AI summary
The present invention is a lithium ion secondary battery comprising a positive electrode and a non-aqueous electrolyte solution comprising a non-aqueous electrolyte solvent, wherein the positive electrode comprises a positive electrode active material having an operating potential at 4.5 V or higher versus lithium metal, the non-aqueous electrolyte solvent comprises a fluorinated phosphate ester represented by a predetermined formula and at least one selected from the group consisting of sulfone compounds represented by predetermined formulae, and the sulfone compound is included in an amount of 5 volume % or more in the non-aqueous electrolyte solvent.