Disulfonic Acid Ester Electrolyte for Lithium Battery Dendrite Suppression
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Solution Overview
Problem
Existing non-aqueous electrolyte secondary batteries face challenges in maintaining stable surface films on negative electrodes, leading to inefficiencies in charge-discharge cycles, safety concerns due to dendrite formation, and increased internal resistance, particularly at high temperatures.
Innovation Solution
A non-aqueous electrolyte containing an aprotic solvent with a disulfonic acid ester having unsaturated bonds, along with sulfonyl compounds and lithium salts, is used to form a stable passive film on the negative electrode, suppressing solvent decomposition and improving cycle life and capacity retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lithium fluoride film is formed by chemical reaction between the negative electrode and hydrofluoric acid in the electrolyte, then dendrite generation is suppressed, but homogeneous film formation becomes difficult due to side reactions and incomplete coverage
Solution Approach 1:
The patent applies preliminary action by forming a lithium fluoride film through chemical reaction before battery operation begins. The electrolyte contains hydrofluoric acid that reacts with the lithium metal negative electrode to form a uniform LiF surface film in advance, preventing dendrite formation during subsequent charge-discharge cycles without requiring additional processing steps.
Solution Approach 2:
The patent utilizes parameter changes by controlling the concentration of hydrofluoric acid in the electrolyte (0.01-5 wt%) and the composition of the negative electrode (lithium metal or lithium alloy with specific Li content). These parameter adjustments optimize the chemical reaction to form a homogeneous LiF film that effectively suppresses dendrites while maintaining good film coverage.
2Stability of the object's composition
If the negative electrode is exposed to atmosphere during handling, then a surface film of lithium hydroxide or lithium oxide forms due to natural oxidation, but this creates inhomogeneous surface that prevents uniform lithium fluoride film formation
Solution Approach 1:
The patent converts the harmful effect of atmospheric oxidation into a beneficial process. The naturally formed lithium hydroxide or lithium oxide surface film reacts with hydrofluoric acid in the electrolyte to form lithium fluoride. This two-step process ensures complete surface coverage and homogeneous film formation, as the initial oxidation layer provides a uniform base for the subsequent LiF formation reaction.
Solution Approach 2:
The patent uses hydrofluoric acid as an intermediary substance that mediates between the oxidized surface (lithium hydroxide/oxide) and the final desired state (lithium fluoride film). The HF reacts with the intermediate oxidation products to form the stable, uniform LiF film, effectively using the intermediate state as a precursor rather than a defect.
3Productivity
If conventional electrolytes are used, then basic battery operation is maintained, but solvent decomposition occurs and cycle life decreases particularly at high temperatures
Solution Approach 1:
The patent applies parameter changes by modifying the electrolyte composition to include hydrofluoric acid at controlled concentrations (0.01-5 wt%). This parameter adjustment changes the chemical environment to promote LiF film formation, which acts as a protective barrier that prevents solvent decomposition and maintains electrolyte stability even at elevated temperatures, thereby extending cycle life.
Solution Approach 2:
The patent uses composite materials by creating a composite surface film structure consisting of lithium fluoride formed through chemical reaction. This LiF-rich surface layer combines the benefits of low reactivity (preventing solvent decomposition) with good ionic conductivity, forming a protective interface that enhances battery durability and thermal stability without compromising electrochemical performance.
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 stabilizes the surface film, enhancing charge-discharge efficiency, cycle life, and reducing internal resistance, while maintaining stability and capacity over extended periods, even at high temperatures.
Implementation Method 1
A non-aqueous electrolyte containing an aprotic solvent with a disulfonic acid ester having unsaturated bonds... is used to form a stable passive film on the negative electrode, suppressing solvent decomposition
Implementation Method 2
non-aqueous electrolyte lithium ions... can realize a high energy density
Data Source
Figure 1
AI summary
A non-aqueous electrolyte can suppress decomposition of a solvent, improve the cycle life of a secondary battery, suppress the rise of resistance of a secondary battery and improve the capacity maintenance ratio of a secondary battery. A non-aqueous electrolyte secondary battery formed by using such a non-aqueous electrolyte includes a non-aqueous electrolyte containing an aprotic solvent and a disulfonic acid ester as expressed by chemical formula 1 shown below, a positive electrode and a negative electrode: