Lithium Battery Electrolyte Additives for Cathode SEI Stability
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Solution Overview
Problem
Lithium secondary batteries face challenges in maintaining uniform output and capacity during repeated charging and discharging, especially in high-temperature environments, due to surface damage of the cathode active material and side reactions with the electrolyte.
Innovation Solution
The development of an electrolyte for lithium secondary batteries that includes specific additives represented by Formulas 1 and 2, which form a stable solid electrolyte interphase (SEI) on the electrode surface, improving high-temperature performance and reducing decomposition and gas generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional electrolytes are used in lithium secondary batteries, then the batteries can operate at high voltage and high energy density, but the cathode active material suffers surface damage and side reactions occur during repeated charging and discharging in high temperature environments
Solution Approach 1:
The patent introduces a mediator substance (additive compound with specific molecular structure containing nitrogen and oxygen atoms) that acts as an intermediary between the cathode active material and the electrolyte. This mediator forms a protective interface layer that prevents direct contact and harmful interactions, thereby resolving the contradiction between maintaining high power operation and ensuring cathode surface stability during repeated charging-discharging cycles
Solution Approach 2:
The patent modifies the chemical composition parameters of the electrolyte by incorporating specific additive compounds with defined molecular structures (containing nitrogen and oxygen atoms in specific ratios). This parameter change in the electrolyte composition enables the formation of a stable protective layer on the cathode surface, allowing the battery to maintain high operating voltage and energy density while preventing cathode degradation during high-temperature operation
2Productivity
If the battery operates in high temperature environments with repeated charging and discharging, then the battery can provide continuous power output, but capacity and output decrease due to cathode surface damage and electrolyte decomposition
Solution Approach 1:
The patent applies preliminary action by having the additive compound react first during initial charging cycles to form a stable protective layer (SEI) on the cathode surface before the harmful degradation processes can occur. This pre-formed protective layer prevents subsequent capacity loss and output degradation during repeated high-temperature charging-discharging cycles, enabling continuous operation while maintaining reliability
Solution Approach 2:
The additive compound serves as a mediator that facilitates continuous charging-discharging operations by forming a stable interface layer between the cathode and electrolyte. This intermediary layer prevents direct harmful interactions while allowing ion transport, thereby enabling continuous productivity without capacity degradation or output instability
3Ease of manufacture
If standard electrolyte composition is used, then the battery can achieve basic performance, but high-temperature lifespan properties are poor with increased decomposition and gas generation
Solution Approach 1:
The patent employs composite materials by combining the standard electrolyte components (lithium salt, organic solvents) with specific additive compounds containing nitrogen and oxygen atoms. This composite electrolyte formulation maintains the basic performance characteristics of standard electrolytes while adding the functional properties needed for high-temperature stability, thereby extending the battery's lifespan without compromising ease of manufacture
Solution Approach 2:
The patent modifies the electrolyte composition parameters by incorporating specific additive compounds at defined concentrations (0.1-5 wt%). This parameter change in the electrolyte formulation enhances the high-temperature lifespan properties by suppressing decomposition reactions and gas generation, while maintaining compatibility with standard manufacturing processes and basic battery 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 proposed electrolyte solution enhances the high-temperature lifespan properties of lithium secondary batteries by suppressing capacity decrease and resistance increase, thereby maintaining high ionic conductivity and capacity retention even under repeated charging and discharging cycles.
Implementation Method 1
specific additives represented by Formulas 1 and 2, which form a stable solid electrolyte interphase (SEI) on the electrode surface
Implementation Method 2
maintaining high ionic conductivity and capacity retention even under repeated charging and discharging cycles
Data Source
Figure 1~2
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AI summary
The electrolyte for a lithium secondary battery according to embodiments of the present disclosure may include an additive including a compound represented by a specific formula, an organic solvent, and a lithium salt. A lithium secondary battery including the electrolyte for a lithium secondary battery according to exemplary embodiments and having improved high-temperature properties, output properties, and lifespan properties may be provided.