Dual-Salt Electrolyte for Lithium Batteries With Dendrite Suppression
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Solution Overview
Problem
Lithium metal batteries suffer from high internal resistance and poor life characteristics due to dendrite formation on the anode, limiting their energy density and longevity.
Innovation Solution
An electrolyte comprising a first lithium salt with high dissociation degree and a second lithium salt with low dissociation degree, combined with a fluorine-containing linear ester solvent, enhances lithium ion conductivity and forms a protective layer to prevent dendrite formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a lithium metal thin film is used as an anode, then energy density is improved, but dendrites are formed and grow on the lithium metal thin film, causing poor life characteristics
Solution Approach 1:
The patent introduces a dual-lithium salt electrolyte system as an intermediary between the lithium metal anode and the battery system. The first lithium salt (high dissociation degree) ensures good ionic conductivity, while the second lithium salt (low dissociation degree) forms a protective interface layer. This intermediary electrolyte system prevents direct harmful interactions between lithium metal and the battery environment, suppressing dendrite growth while maintaining high energy density.
Solution Approach 2:
The patent changes the chemical parameters of the electrolyte by selecting specific lithium salts with contrasting dissociation degrees and using fluorine-containing linear esters as solvents. This parameter optimization creates an electrolyte composition that simultaneously achieves high ionic conductivity and effective dendrite suppression, resolving the contradiction between energy density and life characteristics.
2Reliability
If the electrolyte includes a first lithium salt with high dissociation degree, then lithium ion conductivity is improved, but internal resistance may increase
Solution Approach 1:
The patent optimizes the electrolyte composition parameters by selecting fluorine-containing linear esters as solvents, which have high dielectric constants and low viscosity. These parameter changes enhance the dissociation of lithium salts and improve lithium ion mobility, achieving high ionic conductivity while maintaining low internal resistance through the synergistic effect of solvent and salt selection.
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 reduces internal resistance and improves the life characteristics of lithium batteries by promoting lithium ion conductivity and forming a protective layer on the anode.
Implementation Method 1
a dissociation degree of the first lithium salt with respect to the fluorine-containing linear ester is greater than a dissociation degree of the second lithium salt with respect to the fluorine-containing linear ester
Implementation Method 2
the electrolyte simultaneously includes a first lithium salt and a second lithium salt to form a protective layer that prevents lithium dendrite formation on the anode
Data Source
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AI summary
Provided are an electrolyte and a lithium secondary battery including the same, the electrolyte including: a first lithium salt including a lithium ion and a first anion; a second lithium salt including a lithium ion and a second anion; and a solvent including a fluorine-containing linear ester, wherein a dissociation degree of the first lithium salt with respect to the fluorine-containing linear ester is greater than a dissociation degree of the second lithium salt with respect to the fluorine-containing linear ester.