Lithium Ion Battery Electrolyte Anhydride Additives High Temperature Cycle
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Solution Overview
Problem
Lithium ion batteries face inadequate high-temperature cycle life and poor low-temperature performance due to the limitations of conventional non-aqueous electrolytes, particularly when containing anhydride or anhydride derivatives, which compromise both high-temperature storage and cycle performance.
Innovation Solution
A non-aqueous electrolyte composition for lithium ion batteries, comprising a specific combination of compounds A and B, where compound A is selected from succinic anhydride, maleic anhydride, or 2-methylmaleic anhydride, and compound B includes fluorine-substituted cyclic carbonate compounds, sultones, and unsaturated cyclic carbonates, optimizing the mass content to enhance high-temperature and cycle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If conventional film-forming additives such as vinylene carbonate (VC) are added to non-aqueous electrolyte, then cycle performance and long life are improved, but high-temperature storage performance deteriorates due to gas generation and ballooning
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by introducing a specific anhydride derivative compound with particular molecular structure characteristics. This compound forms a different type of protective film on the electrode surface compared to conventional VC, changing the film-forming mechanism and chemical properties to achieve both long cycle life and good high-temperature storage performance without gas generation
Solution Approach 2:
The patent creates a composite electrolyte system by combining the anhydride derivative compound with conventional electrolyte components (VC, LiPF6, cyclic carbonates, chain carbonates). This composite approach allows the anhydride derivative to form a stable protective film while the conventional components maintain ionic conductivity, achieving synergistic effects that resolve the contradiction between cycle life and high-temperature storage performance
2Duration of action of stationary object
If high content of VC is added to non-aqueous electrolyte, then cycle performance is improved, but low-temperature performance deteriorates due to increased interface impedance
Solution Approach 1:
The patent changes the film-forming mechanism by using anhydride derivative compound instead of relying on high VC content. The anhydride derivative forms a protective film with different impedance characteristics that remains stable at low temperatures, eliminating the need for high VC content and thus avoiding the impedance increase that harms low-temperature performance
Solution Approach 2:
The patent creates a substitute protective film using the anhydride derivative compound that replicates the beneficial effects of VC-based films (protection, stability) without the harmful side effects (high impedance at low temperature). This alternative film-forming approach copies the protective function while improving low-temperature characteristics
3Reliability
If anhydride or anhydride derivatives are added to non-aqueous electrolyte, then high-temperature storage performance is improved, but low-temperature performance deteriorates due to large impedance
Solution Approach 1:
The patent applies local quality by using a specific anhydride derivative compound with particular molecular structure features that enable it to form a protective film with locally optimized properties. This film has high stability at high temperatures (addressing storage performance) while maintaining appropriate ionic conductivity at low temperatures (avoiding the impedance problem of conventional anhydrides), achieving different performance requirements at different temperature conditions
Solution Approach 2:
The patent changes the chemical structure parameters of the anhydride compound by introducing specific substituents or modifying the molecular framework. This structural modification alters the film-forming behavior and electrical properties, enabling the compound to provide high-temperature storage stability without the excessive impedance that plagues conventional anhydrides at low temperatures
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 electrolyte composition significantly improves both high-temperature storage and cycle performance of lithium ion batteries, ensuring better cycle life and stability across varying temperatures.
Implementation Method 1
anhydride or anhydride derivatives can form a coating based on the additive on the negative electrode during charging and discharging processes, thus inhibiting the decomposition of electrolyte
Implementation Method 2
A lithium ion battery is a secondary battery that works by the movement of lithium ions between the positive and negative electrodes
Data Source
AI summary
In order to solve the problem of poor cycle performance (especially high temperature cycle performance) of the existing lithium ion battery electrolyte containing anhydride or anhydride derivatives, the disclosure provides a non-aqueous electrolyte for lithium ion battery. The non-aqueous electrolyte for lithium ion battery comprises a compound A represented by formula I and a compound B represented by formula II, In formula I, R0 is C2-C4 alkylene or alkenylene, or C2-C4fluoroalkylene or fluoroalkenylene; In formula II, R1, R2, R3, R4, R5 and R6 are each independently selected from one of hydrogen atom, halogen atom and C1-C5 group. The non-aqueous electrolyte for lithium ion battery provided by the invention is obtained by combining the compound A and compound B, so that the lithium ion battery containing the non-aqueous electrolyte has better cycle performance and high-temperature storage performance.