High-Nickel Lithium Battery Electrolyte for High-Temperature Stability
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Solution Overview
Problem
Lithium secondary batteries with high-nickel positive electrode materials face degradation issues under high temperature conditions due to electrolyte decomposition and transition metal ion elution, leading to increased resistance and reduced performance.
Innovation Solution
Incorporation of a non-aqueous electrolyte containing a specific combination of additives, including a first additive with succinic anhydride structure and a second additive with a propargyl functional group, forms protective films on the electrodes, reducing gas generation and inhibiting electrolyte decomposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-nickel positive electrode material is used to increase capacity, then initial capacity characteristics are improved, but transition metal ions are eluted during charging and discharging, causing electrodeposition on the negative electrode and film destruction
Solution Approach 1:
The patent introduces a film-forming additive as an intermediary substance in the electrolyte that forms protective films on the electrode surfaces. This additive acts as a mediator between the high-nickel positive electrode and the negative electrode, preventing direct harmful interactions and ion elution while maintaining capacity benefits
Solution Approach 2:
The film-forming additive performs preliminary protective action by forming stable films on the electrode surfaces before harmful elution and electrodeposition processes can occur. This pre-formed protective layer prevents transition metal ion elution from the high-nickel positive electrode during subsequent charging and discharging cycles
2Temperature
If electrolyte decomposition occurs under high temperature conditions, then gas is generated and resistance increases, but battery performance deteriorates
Solution Approach 1:
The patent converts the harmful effect of high temperature into a beneficial outcome by using heat-resistant film-forming additives that form exceptionally stable protective films at elevated temperatures. These films prevent electrolyte decomposition and gas generation, turning the high-temperature challenge into an opportunity to demonstrate enhanced battery stability
Solution Approach 2:
The patent changes the chemical composition parameters of the electrolyte by incorporating specific film-forming additives with high thermal stability. This parameter change enables the formation of protective films that maintain their integrity at high temperatures, preventing electrolyte decomposition and maintaining battery performance
3Reliability
If conventional electrolyte additives are used, then some protection is provided, but insufficient prevention of electrolyte decomposition and transition metal ion elution occurs under high temperature and high-nickel conditions
Solution Approach 1:
The patent employs a composite electrolyte formulation combining multiple film-forming additives with complementary properties. This composite approach creates synergistic effects where the combined additives provide superior protection against both electrolyte decomposition and transition metal ion elution compared to conventional single-additive systems
Solution Approach 2:
The film-forming additives perform preliminary protective action by forming stable films on electrode surfaces during initial cycles or upon contact, preventing subsequent harmful processes. This preliminary film formation blocks ion elution pathways and protects against electrolyte decomposition before these damaging processes can occur
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 additives enhance high-temperature stability and maintain battery performance by minimizing gas generation and electrode degradation, even with high-nickel positive electrode materials.
Implementation Method 1
forms protective films on the electrodes, reducing gas generation and inhibiting electrolyte decomposition
Implementation Method 2
a non-aqueous electrolyte including a lithium salt, an organic solvent
Implementation Method 3
a non-aqueous electrolyte as a medium for transferring lithium ions
Data Source
AI summary
The present invention relates to a lithium secondary battery including: a non-aqueous electrolyte including a lithium salt, an organic solvent, a first additive represented by Chemical Formula 1 and a second additive represented by Chemical Formula 2; a positive electrode including a positive electrode active material including a lithium composite transition metal oxide having a nickel content of 70 mol% or more among a total transition metal content; a negative electrode including an negative electrode active material; and a separator interposed between the positive electrode and the negative electrode.