Cyano Electrolyte Additive for High-Voltage Lithium Battery Cathodes
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Solution Overview
Problem
Lithium ion batteries face capacity degradation due to transition metal dissolution at high-voltage and high-temperature conditions, leading to increased resistance and potential internal short-circuits, which reduces battery lifetime and performance.
Innovation Solution
A non-aqueous electrolyte solution additive represented by Formula 1, containing a cyano group, forms a stable film on the positive electrode surface, suppressing transition metal dissolution and adsorbing metal ions, thereby enhancing battery stability and capacity retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the battery is operated under high-voltage and high-temperature conditions, then the operating voltage and energy density are improved, but transition metal dissolution increases and battery lifetime decreases
Solution Approach 1:
The patent applies preliminary action by forming a protective film on the positive electrode surface before transition metal dissolution can occur. The electrolyte additive decomposes during initial charge/discharge cycles to create a stable film that prevents subsequent metal dissolution, addressing the reliability issue before it manifests during high-voltage operation.
Solution Approach 2:
The patent uses an intermediary substance (electrolyte additive forming SEI film) that mediates between the high-voltage operating conditions and the positive electrode. This film acts as a barrier that allows the battery to operate at high voltage while preventing the harmful interaction between the electrolyte and transition metals in the positive electrode.
2Reliability
If various additives are added to the electrolyte solution to suppress capacity decrease, then battery characteristics are improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies parameter changes by modifying the electrolyte solution composition with specific additives (cyclic carbonate and chain carbonate in controlled ratios, plus 0.01-5 wt% of a specific compound). By carefully controlling the concentration ranges and component ratios, the patent improves battery characteristics while managing the complexity through defined compositional parameters.
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 reduces metallic impurities, improves battery swelling and capacity characteristics, and maintains performance during high-voltage and high-temperature storage, with optimal concentrations balancing metal dissolution suppression and ionic conductivity.
Implementation Method 1
The additive forms a film called a solid electrolyte interphase (SEI) on a surface of an electrode while being decomposed during initial charge and discharge
Implementation Method 2
a compound containing at least one cyano group (…) which may form a stable film on a surface of a positive electrode to prevent dissolution of transition metal
Data Source
AI summary
An additive for a non-aqueous solution of a lithium secondary battery, a non-aqueous electrolyte solution including the same, and a lithium secondary battery include the same are disclosed herein. In some embodiments, an additive is a compound represented by Formula 1. The additive may suppress dissolution of transition metal by forming a stable film on a surface of a positive electrode. A lithium secondary battery including the non-aqueous electrolyte solution having the additive has improved swelling and capacity characteristics at high voltage and during high-temperature storage because dissolution of metallic impurities causing failure in the battery is suppressed.