Spiro-Compound Li-Ion Electrolyte for High-Temperature Gas Suppression
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Solution Overview
Problem
Lithium-ion batteries face challenges with high-temperature storage and cycle performance, particularly due to the instability of the solid electrolyte interface (SEI) film, leading to gas expansion and decreased reversible capacity.
Innovation Solution
A non-aqueous electrolyte comprising a spiro compound, lithium salt, and specific additives like 1,3-propane sultone, which forms a dense passivation film on the positive electrode, enhancing thermal stability and cycle performance by inhibiting solvent decomposition and improving the SEI film composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If vinylene carbonate is added to the electrolyte to improve SEI film quality and cycle performance, then the cycle performance is improved, but the battery produces gas during high-temperature storage leading to swelling
Solution Approach 1:
The patent combines multiple film-forming additives (vinylene carbonate, ethylene sulfite, 1,3-propane sultone) in specific proportions to create a composite electrolyte system. This merging approach allows the additives to work synergistically: vinylene carbonate and ethylene sulfite form stable SEI films on the negative electrode, while 1,3-propane sultone forms protective films on the positive electrode, collectively suppressing gas production during high-temperature storage while maintaining improved cycle performance.
Solution Approach 2:
The patent optimizes the concentration parameters of each additive component. Specifically, it controls vinylene carbonate at 0.01-5% by weight, ethylene sulfite at 0.01-5% by weight, and 1,3-propane sultone at 0.01-5% by weight. By precisely adjusting these parameter ranges, the electrolyte achieves optimal SEI film formation that prevents both capacity degradation and gas expansion during high-temperature storage.
2Object-affected harmful factors
If ethylene sulfite is added to inhibit battery expansion and improve initial capacity, then the battery expansion is reduced, but the SEI film stability deteriorates leading to increased interface resistance
Solution Approach 1:
The patent merges ethylene sulfite with vinylene carbonate and 1,3-propane sultone to create a multi-component film-forming system. Ethylene sulfite provides excellent expansion control and initial capacity enhancement, while vinylene carbonate contributes to SEI film stability and 1,3-propane sultone provides positive electrode protection. The combined system compensates for the individual weaknesses of each additive, achieving both low expansion and high SEI film stability.
Solution Approach 2:
The electrolyte uses a composite approach by combining three different film-forming additives with complementary properties. This composite electrolyte formulation creates a multi-layered protective film structure on the electrodes, where each additive contributes specific functional properties: ethylene sulfite for expansion control, vinylene carbonate for film stability, and 1,3-propane sultone for positive electrode protection, collectively achieving superior overall performance.
3Reliability
If 1,3-propane sultone is added to form dense passivation film on positive electrode, then the electrolyte oxidative decomposition is inhibited, but the high-temperature storage performance deteriorates due to gas production
Solution Approach 1:
The patent combines 1,3-propane sultone with vinylene carbonate and ethylene sulfite in a balanced formulation. The 1,3-propane sultone (0.01-5% by weight) provides excellent positive electrode protection and electrolyte stability under high voltage, while the presence of vinylene carbonate and ethylene sulfite in the mixture suppresses gas production during high-temperature storage by forming stable SEI films on the negative electrode that prevent further decomposition 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 solution significantly improves high-temperature storage and cycle performance, reduces gas expansion, and maintains battery capacity retention, while preventing swelling and electronic polarization.
Implementation Method 1
In the first charging process, the compounds of non-aqueous electrolyte first undergo a reduction and decomposition reaction on the surface of the negative electrode, resulting in compounds such as lithium alkoxy, Li2CO3, lithium sulfonate, etc., and a passivation film is formed on the surface of the negative electrode
Implementation Method 2
In the first charging process, the compounds of non-aqueous electrolyte first undergo a reduction and decomposition reaction on the surface of the negative electrode
Implementation Method 3
The high-voltage additive, represented by 1,3-propane sultone additive, makes the positive electrode active material contact with the electrolyte and inhibits the oxidative decomposition of the electrolyte under high voltage by preferentially generating oxidation reaction on the positive electrode surface and forming a dense passivation film on the positive electrode surface
Implementation Method 4
non-aqueous electrolyte, as a medium for transporting and conducting current between anode and cathode
Data Source
AI summary
The present application belongs to the technical field of new energy, in particular to a non-aqueous electrolyte for a lithium ion battery and a lithium ion battery. The non-aqueous electrolyte for a lithium ion battery comprises a non-aqueous organic solvent, a lithium salt, and a spiro compound represented by Structural Formula 1. The compound represented by Structural Formula 1 has the characteristic of sulfonate additives to improve high-temperature storage performance of battery, and also has the characteristic of sulfate additives to improve high-temperature cycle performance of battery. A passivation film is deposited on the surface of positive electrode, and functional group X is further crosslinked to make the coated passivation film more compact and stable, which can effectively improve the electrochemical performance of the electrode, the storage performance and self-discharge performance of the battery.