Bis(hydroxyacetato)borate Electrolyte Additives for Lithium Battery Stability
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Solution Overview
Problem
Lithium secondary batteries face challenges in maintaining high energy density and stability, particularly in preventing electrolyte permeation through the passivation film and ensuring effective lithium ion mobility, which affects their cycle life and high-temperature performance.
Innovation Solution
Incorporating an organoborate compound as an additive in the electrolyte, represented by Chemical Formula 1c, which forms a non-polar part on the passivation film, reducing reactivity with the electrolyte and lithium ions, and optimizing the electrolyte composition with a non-aqueous organic solvent and lithium salt to enhance electrochemical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolytes are used, then lithium ion mobility is maintained, but electrolyte permeation through the passivation film occurs, reducing cycle life and high-temperature stability
Solution Approach 1:
The organoborate compound acts as an intermediary substance that modifies the passivation film properties. It forms a non-polar part on the passivation film surface, creating a barrier layer that reduces electrolyte permeation while maintaining lithium ion mobility. This intermediary compound bridges the electrolyte and passivation film interfaces to achieve both protection and ion transport.
Solution Approach 2:
The invention changes the chemical composition parameters of the electrolyte by introducing the organoborate compound with specific molecular structure (Formula 1c). This parameter change modifies the passivation film characteristics, reducing its polarity and permeability to electrolyte while maintaining conductivity for lithium ions, thereby improving reliability without sacrificing ion mobility.
2Stability of the object's composition
If the passivation film is made more resistant to electrolyte permeation, then stability improves, but lithium ion mobility may be reduced
Solution Approach 1:
The organoborate compound creates local quality changes in the passivation film by forming a non-polar part on its surface. This localized modification allows the film to have different properties in different regions: the non-polar surface layer resists electrolyte permeation for stability, while the underlying structure maintains lithium ion mobility. The additive selectively modifies only the surface characteristics without compromising bulk ion transport 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 organoborate additive improves the cycle life and high-temperature stability of lithium secondary batteries by reducing electrolyte permeation and maintaining effective lithium ion mobility, leading to higher discharge capacity retention and reduced self-discharge.
Implementation Method 1
forms a non-polar part on the passivation film, reducing reactivity with the electrolyte and lithium ions
Implementation Method 2
An electrolyte includes an organic solvent in which a lithium salt is dissolved
Implementation Method 3
Batteries transform chemical energy generated from an electrochemical redox reaction of a chemical material in the battery into electrical energy
Data Source
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AI summary
The present invention refers to a compound for an electrolyte of a lithium secondary battery. The invention further concerns about an electrolyte including the compound as well as a lithium secondary battery including the electrolyte. The compound is represented by the following Chemical Formula 1: wherein R1 to R4 are each independently hydrogen or a unsubstituted hydrocarbon group. Specific disclosures according to the Markush formula are: Formulae 1a to 1c: