Organic Ester Electrolyte for Stable High-Voltage Lithium Batteries
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Solution Overview
Problem
Conventional carbonate-based solvents in lithium secondary batteries degrade battery characteristics when used with high-voltage cathodes, leading to reduced performance and stability over time.
Innovation Solution
An electrolyte comprising an organic ester compound with multiple ester groups, combined with an organic solvent and a lithium salt, forms a stable solid electrolyte interface (SEI) membrane, enhancing the battery's stability and performance by improving the interfacial resistance and ion mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional carbonate-based solvent is used as electrolyte solvent, then the battery can operate with high energy density, but the battery characteristics degrade over lifetime when used with high-voltage cathode
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by introducing organic ester compounds with multiple ester groups (Formula 1) containing specific alkyl or cycloalkyl substituents. This chemical parameter change enables the electrolyte to form stable SEI films on high-voltage cathodes while maintaining high energy density, thus resolving the contradiction between energy density and reliability.
Solution Approach 2:
The patent creates a composite electrolyte system by combining organic ester compounds (Formula 1) with conventional carbonate-based solvents and lithium salts. This composite approach allows the organic ester component to provide stability and protective film formation, while the carbonate component maintains high energy density and ion conductivity, thereby simultaneously achieving both reliability and energy density.
2Reliability
If conventional carbonate-based solvent is used, then the electrolyte provides good ion conductivity, but the interfacial resistance increases and performance degrades over time
Solution Approach 1:
The organic ester compound in the electrolyte performs preliminary action by forming a stable protective film (SEI) on the cathode surface before significant degradation can occur. This pre-formed protective layer prevents subsequent interfacial resistance increase and performance degradation, thereby extending battery lifetime while maintaining good ion mobility.
Solution Approach 2:
The organic ester compound acts as a sacrificial component that decomposes preferentially to form stable protective films, sacrificing itself to protect the main electrolyte system and battery components. This disposable-like behavior of the organic ester additive extends the overall battery lifetime while maintaining ion mobility.
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 organic ester compound-based electrolyte improves the discharge capacity and cycle stability of lithium secondary batteries, maintaining high performance and extending the battery's lifespan by preventing gasification and enhancing ion conductivity.
Implementation Method 1
forms a stable solid electrolyte interface (SEI) membrane, enhancing the battery's stability and performance by improving the interfacial resistance and ion mobility
Implementation Method 2
maintaining high performance and extending the battery's lifespan by preventing gasification and enhancing ion conductivity
Implementation Method 3
enhancing ion conductivity
Data Source
AI summary
An electrolyte for a lithium secondary battery, the electrolyte including: an organic ester compound represented by Formula 1; an organic solvent; and a lithium salt:wherein, in Formula 1, R1, R2, and R3 are the same or different, and are each independently a group represented by Formula 2:wherein, in Formula 2, R′ is a C1-C10 alkyl group or a C3-C10 cycloalkyl group.