Lithium Battery Electrolyte Additive for Overcharge Protection
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Solution Overview
Problem
Current redox shuttle additives in lithium batteries are insufficient for ensuring safety in high-capacity batteries, as they fail to adequately prevent overcharging and thermal runaway, leading to potential explosions and safety hazards.
Innovation Solution
An electrolyte composition including a non-aqueous organic solvent, a lithium salt, and a specific additive represented by Formula 1, which initiates polymerization at high voltages to increase electrode resistance and consume overcharge current, thereby enhancing battery safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional redox shuttle additives are used in high-capacity lithium batteries, then some overcharge protection is provided, but the battery safety is insufficient and thermal runaway cannot be effectively prevented
Solution Approach 1:
The patent changes the chemical parameters of the additive by introducing specific heteroatom-containing structures (sulfur, nitrogen, oxygen) and functional groups to the redox shuttle molecule. This modification raises the oxidation potential and alters the reaction characteristics, enabling the additive to effectively suppress thermal runaway at high temperatures while maintaining overcharge protection functionality in high-capacity batteries
Solution Approach 2:
The patent creates a composite functional additive that combines multiple chemical functionalities within a single molecular structure: redox shuttle capability for overcharge protection, heteroatom-containing groups for enhanced thermal stability, and specific functional groups for controlled polymerization. This composite structure simultaneously addresses multiple safety concerns that conventional single-function additives cannot resolve
2Quantity of substance
If the battery capacity is increased to meet high energy density requirements, then more lithium ions are stored, but the risk of overcharging and thermal runaway increases
Solution Approach 1:
The modified redox shuttle additive acts in advance by establishing a protective interface layer on the electrode surfaces before excessive lithium deposition occurs. The additive undergoes controlled polymerization and forms a stable film that prevents subsequent thermal runaway, even when large amounts of lithium ions are cycled in high-capacity batteries
Solution Approach 2:
The heteroatom-containing functional groups in the additive serve as intermediaries between the electrolyte and electrode surfaces. These groups facilitate controlled reactions that consume excess lithium ions through polymerization and redox reactions, mediating the interaction between high lithium ion flux and electrode materials to prevent direct harmful reactions
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 effectively inhibits overcharging and thermal runaway, improving safety characteristics and maintaining high-capacity battery performance by using the additive to coat electrode surfaces and perform oxidation/reduction reactions at elevated voltages.
Implementation Method 1
the polymerization reaction of these redox shuttle additives consumes the overcharge current to improve battery safety
Implementation Method 2
an aromatic compound, such as biphenyl, 3-chlorothiophene, furan, etc., which is electrochemically polymerized to increase the internal resistance of a battery during unusual overvoltage conditions
Implementation Method 3
close pores of a separator through quick and uniform fusion of the separator to inhibit an overcharge reaction
Data Source
AI summary
The electrolyte for a lithium battery includes a non-aqueous organic solvent, a lithium salt, and an additive of the following Formula 1:wherein, X is O or S,Y1, Y2, and Y3 are the same or different from each other and selected from the group consisting of O, S, CR2, and NR, where here R is H, a halogen, or an alkyl having a carbon number of less than or equal to 8, or neighboring alkyl groups are combined to each other to form a cycle or hetero cycle, andRa to Rd are the same or different from each other and selected from H, a halogen, an alkoxy group having a carbon number of less than or equal to 8, or an unsaturated or saturated alkyl group having a carbon number of less than or equal to 8, or neighboring alkyl groups are combined to each other to form a cycle or hetero cycle.