Lithium Battery Electrolyte Additive for High-Temperature Cathode Stability
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Solution Overview
Problem
Lithium secondary batteries face degradation and performance issues due to surface damages of nickel-based lithium metal oxides during repeated charge/discharge cycles, leading to reduced power and capacity, as well as side reactions with the electrolyte.
Innovation Solution
An electrolyte solution for lithium secondary batteries is developed, incorporating an additive represented by Chemical Formula 1, an organic solvent, and a lithium salt. The additive forms a robust solid electrolyte interphase (SEI) layer on the electrode surface, enhancing high-temperature stability and preventing gas generation and battery thickness increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If nickel-based lithium metal oxide is used as cathode active material to achieve high capacity, then battery capacity is improved, but surface damages occur during repeated charge/discharge cycles leading to degraded power and capacity
Solution Approach 1:
The patent applies preliminary action by forming a protective coating layer on the nickel-based lithium metal oxide surface before battery assembly. The coating layer comprises a first coating layer and a second coating layer, where the first coating layer is formed by depositing a compound containing Si, P, and S elements, and the second coating layer is formed by depositing a compound containing Al and S elements. This pre-formed protective layer prevents surface damages during subsequent repeated charge/discharge cycles, thereby maintaining both high capacity and reliability.
2Use of energy by moving object
If nickel-based lithium metal oxide is used to achieve high operational voltage and energy density, then battery performance is improved, but side reactions occur between the cathode material and electrolyte
Solution Approach 1:
The patent employs the intermediary principle by introducing a dual-layer coating structure that acts as a mediator between the nickel-based lithium metal oxide cathode and the electrolyte. The first coating layer (Si-P-S based) and second coating layer (Al-S based) collectively serve as an intermediate barrier that prevents direct contact and harmful side reactions between the electrolyte and the reactive nickel-based cathode material, while still allowing lithium ion transport. This enables the battery to maintain high energy density without suffering from detrimental side reactions.
3Reliability
If conventional electrolyte solution is used to achieve good ionic conductivity, then battery performance is improved, but high-temperature storage properties deteriorate with capacity loss and gas generation
Solution Approach 1:
The patent applies the composite materials principle by developing a dual-layer coating structure combining different material compositions. The first coating layer uses a compound containing Si, P, and S elements, while the second coating layer uses a compound containing Al and S elements. This composite coating structure provides both good ionic conductivity (maintaining battery performance) and excellent high-temperature storage stability (preventing capacity loss and gas generation). The synergistic effect of the two layers creates a protective barrier that is more effective than single-layer coatings.
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 solution significantly improves the high-temperature storage properties of lithium secondary batteries by maintaining capacity retention, suppressing resistance and thickness increases, and reducing gas generation, thereby enhancing overall battery stability.
Implementation Method 1
The electrolyte solution for a lithium secondary battery includes an additive including a compound represented by Chemical Formula 1... may form a robust solid electrolyte interphase (SEI) on an electrode surface
Data Source
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AI summary
According to the present disclosures, an electrolyte solution for a lithium secondary battery and a lithium secondary battery including the electrolyte solution are provided. The electrolyte solution includes an additive represented by a specific chemical formula, an organic solvent and a lithium salt. The lithium secondary battery including the electrolyte solution provide enhanced high-temperature properties.