4-Fluoro-1,3-Dioxolane-2-One Electrolyte for High-Density Lithium Anodes
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Solution Overview
Problem
Lithium ion secondary batteries using carbon materials for the anode face challenges in increasing energy density and cycle characteristics due to limitations in the thickness and volume density of the anode active material layer, leading to lithium metal precipitation and decreased performance.
Innovation Solution
A battery design incorporating a cathode and anode with optimized thickness and volume density, utilizing an electrolytic solution containing 4-fluoro-1,3-dioxolane-2-one, lithium hexafluorophosphate, and vinylene carbonate to enhance lithium diffusion and acceptance, preventing lithium metal precipitation and improving energy density and cycle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of the anode active material layer is increased to improve energy density, then the energy density is improved, but the current density to the anode is increased causing lithium metal precipitation and poor cycle characteristics
Solution Approach 1:
The patent introduces 4-fluoro-1,3-dioxolane-2-one as an intermediary substance in the electrolytic solution that mediates between the anode active material layer and lithium ions. This intermediary forms a protective coating on the anode surface that facilitates lithium diffusion and prevents lithium metal precipitation, enabling the use of thicker anode active material layers without sacrificing cycle characteristics.
2Quantity of substance
If the volume density of the anode active material layer is increased to improve energy density, then the energy density is improved, but lithium diffusion and acceptance are hindered causing lithium metal precipitation
Solution Approach 1:
4-fluoro-1,3-dioxolane-2-one acts as a mediator that enhances lithium diffusion and acceptance in high volume density anode active material layers. The substance forms a conductive coating that maintains lithium ion transport pathways even in densely packed anode structures, preventing lithium metal precipitation while preserving high energy density.
Solution Approach 2:
The patent changes the chemical composition parameter of the electrolytic solution by incorporating 4-fluoro-1,3-dioxolane-2-one, which alters the interface properties between the electrolyte and anode. This parameter change enables improved lithium diffusion and acceptance in high volume density anode active material layers, resolving the contradiction between energy density and lithium productivity.
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 battery design effectively increases energy density and cycle characteristics by improving lithium diffusion and acceptance, even with increased anode active material layer thickness and volume density, while maintaining high performance.
Implementation Method 1
the electrolytic solution contains 4-fluoro-1,3-dioxolane-2-one. Therefore, a favorable coating can be formed on the anode
Implementation Method 2
the diffusion and acceptance of lithium in the anode can be improved
Data Source
AI summary
A battery capable of obtaining a high energy density and obtaining superior cycle characteristics is provided. The thickness of a cathode active material layer is from 100 μm to 130 μm. The thickness of an anode active material layer is from 85 μm to 120 μm, and the volume density of the anode active material layer is from 1.7 g/cm3 to 1.85 g/cm3. An electrolytic solution contains 4-fluoro-1,3-dioxolane-2-one. Thereby, even when the thicknesses of the cathode active material layer and the anode active material layer are increased, the diffusion and acceptance of lithium in an anode are improved, and superior cycle characteristics can be obtained.