Lithium Battery Electrolyte Additive for High-Temperature Stability
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Solution Overview
Problem
Lithium batteries face challenges with high-temperature stability and resistance increase due to the degradation of electrolytes and electrodes, particularly when using nickel-rich lithium-nickel-based composite oxides, which can lead to reduced lifespan and capacity.
Innovation Solution
Incorporating a compound represented by Formula 1 into the electrolyte, which forms a sulfonate-based polymer film, enhances the stability of the SEI layer and reduces the deposition of transition metals, thereby improving the high-temperature characteristics and lifespan of lithium batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If nickel-rich lithium-nickel-based composite oxides are used in the positive electrode, then energy density and capacity are improved, but high-temperature stability deteriorates and resistance increases
Solution Approach 1:
A cyclic sulfate ester compound (Formula 1) is introduced as an intermediary additive in the electrolyte. This compound mediates between the nickel-rich cathode material and the electrolyte, forming a protective interface layer that prevents direct harmful interactions. The additive acts as a buffer that stabilizes the electrode-electrolyte interface at high temperatures while maintaining the high capacity benefits of nickel-rich materials.
Solution Approach 2:
The chemical composition parameters of the electrolyte are modified by incorporating cyclic sulfate ester compounds with specific molecular structures (Formula 1). By changing the electrolyte composition parameters - specifically adding compounds with sulfonate groups and specific R1-R4 substituents - the electrolyte's interaction characteristics with the nickel-rich cathode are altered, improving high-temperature stability without sacrificing energy density.
2Quantity of substance
If nickel-rich lithium-nickel-based composite oxides are used in the positive electrode, then capacity is improved, but lifespan is reduced due to electrode degradation
Solution Approach 1:
The cyclic sulfate ester compound performs preliminary protective action by forming a stable interface layer during initial cycles and throughout battery operation. This pre-formed protective layer prevents subsequent degradation reactions between the nickel-rich cathode and electrolyte, thereby extending battery lifespan while maintaining high capacity. The additive proactively prevents damage rather than reacting to it.
Solution Approach 2:
The high reactivity of nickel-rich cathode materials, which normally causes degradation and reduces lifespan, is converted into a benefit. The cyclic sulfate ester compound utilizes this reactivity to form a highly stable and conductive interface layer that actually protects the electrode. The potentially harmful high reactivity is transformed into a useful protective mechanism that enhances both performance and longevity.
3Ease of manufacture
If conventional electrolytes are used with nickel-rich cathodes, then manufacturing simplicity is maintained, but resistance increases at high temperature
Solution Approach 1:
The electrolyte composition parameters are adjusted by adding small amounts (0.01-5 wt%) of cyclic sulfate ester compounds to conventional electrolyte formulations. This parameter change - incorporating specific additives with sulfonate groups - modifies the electrolyte's high-temperature behavior, suppressing resistance increase while maintaining ease of manufacturing through simple mixing processes.
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 use of the compound in the electrolyte results in a lithium battery with enhanced high-temperature stability, suppressed resistance increase, and extended lifespan, even when using nickel-rich lithium-nickel-based composite oxides.
Implementation Method 1
the compound represented by Formula 1, which forms a sulfonate-based polymer film
Implementation Method 2
reduces the deposition of transition metals
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A lithium battery comprising a positive electrode, the positive electrode comprising a lithium-nickel-based composite compound that contains about 50 mol% to about 100 mol% of nickel with respect to a total amount of transition metal; a negative electrode; and an electrolyte, wherein the electrolyte comprises a lithium salt and a compound represented by the following Formula 1: