Battery Electrolyte Additive for High-Temperature Cathode Protection
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Solution Overview
Problem
Lithium-ion batteries face degradation due to the dissolution of transition metals from the positive electrode during high-temperature storage, leading to increased resistance and reduced capacity.
Innovation Solution
A non-aqueous electrolyte solution additive, represented by Formula 1, is introduced to form a robust film on the positive electrode surface and scavenge Lewis acids, thereby suppressing transition metal dissolution and enhancing high-temperature stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium salt (LiPF6) is used in the electrolyte solution, then ionic conductivity is improved, but thermal stability deteriorates causing Lewis acid generation and transition metal dissolution
Solution Approach 1:
A compound of Formula 1 is introduced as an intermediary substance between the lithium salt and the positive electrode. This compound preferentially reacts with Lewis acids generated from lithium salt decomposition, forming a protective film on the positive electrode surface. The intermediary compound thus mediates between the ionic conductivity requirement (lithium salt) and thermal stability requirement, preventing direct harmful interactions while maintaining electrolyte functionality.
Solution Approach 2:
The invention converts the harmful Lewis acids (PF5, HF) generated from lithium salt thermal decomposition into beneficial protective film components. The compound of Formula 1 reacts with these Lewis acids to form a stable surface film on the positive electrode, thereby transforming the decomposition products from harmful substances into protective elements that prevent transition metal dissolution.
2Temperature
If high-temperature storage is performed, then battery capacity is improved, but transition metal dissolution increases leading to resistance increase
Solution Approach 1:
The compound of Formula 1 performs preliminary protection by forming a stable surface film on the positive electrode before high-temperature storage conditions cause significant transition metal dissolution. This pre-formed film acts as a barrier that prevents or reduces metal ion release into the electrolyte during subsequent high-temperature operation, thereby maintaining resistance stability.
Solution Approach 2:
The invention changes the chemical composition parameters of the electrolyte system by introducing the compound of Formula 1 with specific molecular structure characteristics. This parameter change modifies the interfacial chemistry between electrolyte and electrode, creating a more thermally stable interface that resists transition metal dissolution even at elevated temperatures.
3Stability of the object's composition
If transition metal dissolution is suppressed, then electrode stability is improved, but electrolyte composition complexity increases
Solution Approach 1:
The compound of Formula 1 provides localized protection at the positive electrode-electrolyte interface rather than requiring bulk modification of the entire electrolyte system. By concentrating the protective function at the critical interface where transition metal dissolution occurs, the invention achieves electrode stability enhancement with minimal impact on overall electrolyte composition and properties.
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 additive effectively prevents the dissolution of transition metals and improves the high-temperature stability and cycle characteristics of lithium-ion batteries by forming a stable film and scavenging decomposition products.
Implementation Method 1
forms a robust film on a surface of a positive electrode
Implementation Method 2
The additive effectively prevents the dissolution of transition metals and improves the high-temperature stability and cycle characteristics of lithium-ion batteries by forming a stable film
Implementation Method 3
scavenging by-products (HF and PF5, etc.), which are generated by the thermal decomposition of the lithium salt
Implementation Method 4
the lithium salt generates a Lewis acid, such as PF5, while being thermally decomposed when the battery is exposed to high temperatures
Implementation Method 5
an electrolyte solution that becomes a medium for transferring lithium ions
Data Source
AI summary
An electrolyte solution additive, an electrolyte solution including the same, and a lithium secondary battery including the same are disclosed herein. In some embodiments, an electrolyte solution additive includes a compound represented by Formula 1:Wherein X is oxygen (O) or sulfur (S), and R is a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms or N(R1)2, wherein R1 is hydrogen or a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms. The additive has an excellent effect of scavenging a decomposition product generated from a lithium salt and simultaneously forming a robust film on a surface of a positive electrode.