Lithium Battery Electrolyte Additive for High-Temperature Capacity Retention
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Solution Overview
Problem
Lithium secondary batteries face challenges with high-temperature performance, including capacity degradation, increased internal resistance, and swelling due to side reactions between the nickel-based lithium metal oxide cathode and the electrolyte.
Innovation Solution
The use of an electrolyte comprising an additive represented by Formula 1, an organic solvent, and a lithium salt, which forms a robust solid electrolyte interphase (SEI) on the electrode surface, thereby reducing gas generation and battery thickness increase, and improving lithium ion mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If nickel-based lithium metal oxide is used as cathode active material to achieve high capacity, then battery capacity is improved, but side reactions with electrolyte occur causing capacity degradation and increased internal resistance
Solution Approach 1:
The patent introduces a specific additive compound (Formula 1) as an intermediary substance between the nickel-based cathode and the electrolyte. This additive forms a protective interface layer that mediates the interaction, preventing direct harmful side reactions while allowing beneficial lithium ion transport, thus resolving the contradiction between high capacity and capacity retention
Solution Approach 2:
The patent modifies the chemical composition parameters of the electrolyte by incorporating the specific additive from Formula 1 with defined structural parameters (R1, R2, L1 groups). This parameter change in the electrolyte composition alters the interfacial properties between electrode and electrolyte, reducing side reactions while maintaining high capacity performance
2Productivity
If repeated charging and discharging is performed to achieve high productivity, then battery output is improved, but damage to cathode surface accelerates causing deterioration in lifespan characteristics
Solution Approach 1:
The additive in Formula 1 performs preliminary protective action by forming a stable surface modification layer on the cathode before repeated charging/discharging cycles begin. This pre-formed protective layer prevents subsequent damage accumulation during high-speed cycling, thereby extending lifespan while maintaining productivity
Solution Approach 2:
The additive acts as a mediator that enables high-speed charging by facilitating smooth lithium ion transport while simultaneously protecting the cathode surface from damage during repeated cycles, thus resolving the contradiction between productivity and lifespan
3Speed
If battery is placed in high-temperature environment to achieve rapid charge performance, then charging speed is improved, but swelling phenomenon and increase in internal resistance are accelerated
Solution Approach 1:
The patent changes the thermal stability parameters of the electrolyte system by incorporating the heat-resistant additive from Formula 1. This parameter change enables the battery to maintain stable chemical properties at high temperatures, allowing rapid charging without accelerating degradation or swelling
Solution Approach 2:
The additive serves as a thermal mediator that stabilizes the electrode-electrolyte interface at elevated temperatures during rapid charging, preventing harmful thermal side reactions while maintaining efficient charge transfer
4Ease of manufacture
If conventional electrolyte composition is used to simplify manufacturing, then ease of manufacture is improved, but uniform output and capacity during repeated charging and discharging are not achieved
Solution Approach 1:
The patent optimizes the compositional parameters of the electrolyte by incorporating the specific additive from Formula 1 at defined concentration ranges. This parameter optimization achieves uniform output during cycling while maintaining relatively simple manufacturing processes, balancing ease of manufacture with performance stability
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 high-temperature storage characteristics by maintaining capacity retention, reducing resistance and thickness increases, and improving rapid charge performance and lifespan capacity retention.
Implementation Method 1
The electrolyte for a lithium secondary battery may include: an additive which includes a compound represented by Formula 1 below; an organic solvent; and a lithium salt
Implementation Method 2
improving lithium ion mobility
Data Source
Figure 1~2
Figure 3
AI summary
According to exemplary embodiments, an electrolyte for a lithium secondary battery which includes an additive including a compound represented by a specific formula; an organic solvent; and a lithium salt may be provided. Thereby, the lithium secondary battery including the electrolyte for a lithium secondary battery may provide excellent high-temperature characteristics and other performances (e.g., initial resistance, rapid charge performance, room-temperature capacity characteristics, etc.).