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 high safety in high-capacity batteries, as they cannot effectively prevent overcharging and thermal runaway, leading to potential explosions.
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 over 4.5V to increase electrode resistance and consume overcharge current, preventing thermal runaway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional redox shuttle additives are used in high-capacity lithium batteries, then the battery capacity is increased, but the safety is deteriorated due to inability to prevent overcharging and thermal runaway
Solution Approach 1:
The patent changes the chemical parameters of the additive by introducing a specific molecular structure with heteroatoms (O, S, or NR) at the 4-position of the aromatic ring. This structural parameter change enables the additive to undergo oxidation-reduction reactions at higher potentials, allowing it to effectively inhibit overcharging in high-capacity batteries without causing thermal runaway, thus resolving the safety issue while maintaining high capacity
Solution Approach 2:
The patent creates a composite electrolyte system by combining the specific aromatic compound additive (Formula 1) with conventional redox shuttle additives and electrolyte solvents. This composite approach synergistically enhances both the overcharge protection capability and thermal stability, enabling the battery to achieve high capacity with improved safety
2Reliability
If aromatic compounds are used as redox shuttle additives, then overcharge current is consumed through polymerization reaction, but the temperature inside the battery increases early due to heat production
Solution Approach 1:
The patent changes the electrochemical parameters of the additive by designing a structure with heteroatoms (O, S, or NR) that shifts the oxidation-reduction potential to higher values. This parameter change allows the additive to react at potentials closer to the operating voltage, reducing unnecessary heat generation from early polymerization while still effectively consuming overcharge current, thus protecting against overcharge without excessive temperature increase
3Reliability
If the additive structure includes heteroatoms (O, S, or NR) at the 4-position, then the oxidation-reduction potential is increased, but the synthesis complexity increases
Solution Approach 1:
The patent strategically places heteroatoms (O, S, or NR) at the specific 4-position of the aromatic ring structure, which is a precise parameter change that maximizes the oxidation-reduction potential with minimal structural modification. This targeted approach achieves high overcharge inhibition capability while keeping the overall molecular structure relatively simple and synthesizable, balancing performance enhancement with manufacturing feasibility
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 effectively inhibits overcharging and enhances battery safety by preventing thermal runaway and ignition, maintaining high discharge capacity and performance.
Implementation Method 1
the polymerization reaction of these redox shuttle additives consumes the overcharge current to improve battery safety
Implementation Method 2
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, S, CR2 or 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,Y1, and Y2 are the same or different from each other and selected from 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,Y3 is S, CR2, or 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, neighboring alkyl groups are combined to each other to form a cycle or hetero cycle.