Lithium Battery Electrolyte Additives for High-Temperature Durability
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Solution Overview
Problem
Lithium secondary batteries face issues with lifespan characteristics and long-term durability due to side reactions between the negative/positive electrode and the organic electrolyte, leading to decreased performance at high temperatures.
Innovation Solution
An electrolyte composition for lithium secondary batteries is introduced, comprising a lithium salt, an organic solvent, and additives such as isocyanate-based and carbonate-based additives, with a specific weight ratio of carbonate-based to isocyanate-based additives greater than 1, which forms a protective film reducing internal resistance and enhancing stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If an organic electrolyte containing a lithium salt is used as an electrolyte for a lithium secondary battery, then the battery can operate at high driving voltage, but the lifespan characteristics and long-term durability may deteriorate due to side reactions between electrodes and the electrolyte
Solution Approach 1:
A coating layer comprising a cyclic carboxylate and a lithium salt is formed on the surface of the positive electrode, acting as an intermediary barrier between the electrode and the organic electrolyte. This coating layer suppresses side reactions while maintaining high voltage operation, thereby improving both lifespan characteristics and long-term durability without sacrificing power output
2Power
If an organic electrolyte containing a lithium salt is used as an electrolyte for a lithium secondary battery, then the battery can operate at high driving voltage, but the high-temperature stability deteriorates due to side reactions between electrodes and the electrolyte
Solution Approach 1:
The coating layer comprising a cyclic carboxylate and a lithium salt serves as a protective intermediary that prevents direct contact between the electrode and the organic electrolyte. This barrier effect suppresses thermally activated side reactions at high temperatures, thereby maintaining high-temperature stability while preserving the battery's high voltage operating characteristics
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 proposed electrolyte composition significantly improves the long-term durability and lifespan characteristics of lithium secondary batteries by reducing internal resistance, suppressing nickel elution, and maintaining high-temperature stability.
Implementation Method 1
an isocyanate-based additive may improve battery characteristics by forming a film that induces improvement in long-term durability of a battery through surface reactions after chemical adsorption on the surface of an electrode
Data Source
AI summary
Disclosed are an electrolyte for a lithium secondary battery and a lithium secondary battery including the same, the electrolyte including: a lithium salt; an organic solvent; and an additive, wherein the additive includes an isocyanate-based additive and a carbonate-based additive, wherein the ratio of the weight of the carbonate-based additive to the weight of the isocyanate-based additive is greater than 1.