Rechargeable Battery Electrolyte for High-Density Anode Cycle Life
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Solution Overview
Problem
Increasing the density of the negative electrode in rechargeable lithium batteries leads to a decrease in cycle-life and an increase in battery thickness due to reduced void volumes and increased electrolyte impregnation.
Innovation Solution
An electrolyte composition for rechargeable lithium batteries that includes a lithium salt, a non-aqueous organic solvent, and specific additives represented by Chemical Formulas 1 and 2, which act as surfactants to improve wettability and prevent lithium dendrite precipitation, thereby maintaining battery thickness and cycle-life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the density of the negative electrode is increased to improve energy density, then the battery capacity increases, but the void volumes decrease causing increased electrolyte impregnation which increases battery thickness and decreases cycle-life
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by introducing specific additives (cyclic carboxylate and cyclic carbonate in controlled ratios) to modify the electrolyte's interaction with the electrode. This allows achieving both high energy density and long cycle-life by optimizing the chemical parameters of the electrolyte system
Solution Approach 2:
The patent uses a composite electrolyte system combining multiple components (lithium salt, cyclic carboxylate, cyclic carbonate, and linear carbonate) working together. The synergistic interaction between these composite components enables the electrolyte to simultaneously provide high ionic conductivity for energy density and stable SEI formation for cycle-life
2Quantity of substance
If the density of the negative electrode is increased, then the energy density improves, but the battery thickness increases due to reduced void volumes and increased electrolyte impregnation
Solution Approach 1:
The patent modifies the electrolyte's physical and chemical parameters by adding specific cyclic carboxylate and cyclic carbonate components. These parameter changes enable the electrolyte to achieve optimal impregnation characteristics that prevent excessive thickness increase while maintaining high energy density
3Quantity of substance
If conventional electrolytes are used with high-density negative electrodes, then energy density increases, but lithium dendrites precipitate and cycle-life decreases
Solution Approach 1:
The cyclic carboxylate and cyclic carbonate additives act as intermediary substances that mediate between the lithium ions and the electrode surface. They form stable intermediate SEI structures that prevent lithium dendrite precipitation while enabling high energy density operation
Solution Approach 2:
The patent changes the chemical composition parameters of the electrolyte to include specific ratios of cyclic carboxylate and cyclic carbonate, which fundamentally alters the electrolyte's interaction with lithium ions and prevents dendrite formation
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 effectively suppresses the increase in battery thickness and maintains cycle-life even when the negative electrode density is increased, by enhancing the wettability of electrodes and stabilizing the SEI film.
Implementation Method 1
the first additive and the second additive concurrently used as a surfactant
Implementation Method 2
a stable SEI film is formed at an interface between the negative electrode and the electrolyte, thereby suppressing the precipitation of lithium dendrites
Data Source
AI summary
An electrolyte for a rechargeable lithium battery may include a lithium salt; a non-aqueous organic solvent; a first additive represented by Chemical Formula 1; and a second additive represented by Chemical Formula 2:R1—O—R2 Chemical Formula 1R3—O—R4. Chemical Formula 2The description of each chemical formulas follows the specification.