Lithium Battery Electrolyte Additive for Protective Electrode Films
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Solution Overview
Problem
Lithium secondary batteries face challenges in maintaining high energy density and stability due to interfacial reactivity between electrolyte solutions and electrodes, leading to degradation and reduced charging and discharging performance.
Innovation Solution
An electrolyte solution comprising a lithium salt, solvent, and a functional additive, specifically 4-((tert-butoxydimethylsilyl)methyl)-5-methyl-1,3-dioxol-2-one, which forms protective films on electrode surfaces to enhance ion conductivity and prevent degradation, along with vinylene carbonate as a negative electrode film additive.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-capacity electrode materials are used to increase energy density, then battery capacity is improved, but interfacial reactivity between electrolyte and electrodes increases causing decomposition and performance deterioration
Solution Approach 1:
The patent introduces a silane-based additive (containing Si-O-C or Si-C bonds) as an intermediary substance between the electrolyte and electrode materials. This additive preferentially reacts with electrode surfaces to form a stable protective film that acts as a barrier, preventing direct contact and harmful reactions between the electrolyte and high-capacity electrode materials, thus resolving the contradiction between high capacity and electrolyte stability
Solution Approach 2:
The patent modifies the chemical composition parameters of the electrolyte by incorporating specific silane compounds with controlled concentrations (0.01-5 wt%). This parameter change transforms the electrolyte system from one that directly contacts electrodes to one that forms a modified interface with improved stability, enabling the use of high-capacity materials without suffering from interfacial decomposition
2Reliability
If electrolyte additives are increased to form protective films, then electrode protection is improved, but cell resistance increases reducing power output
Solution Approach 1:
The patent optimizes the concentration parameter of silane additives within a specific range (0.01-5 wt%, preferably 0.1-1 wt%). This precise parameter control ensures that sufficient protective film is formed to protect electrodes from decomposition, while avoiding excessive film thickness that would increase cell resistance and reduce power output. The optimal concentration balance resolves the contradiction between protection and power
Solution Approach 2:
The patent employs composite electrolyte formulations combining silane-based additives with conventional electrolyte components (carbonate solvents and lithium salts). This composite approach creates a synergistic system where the silane forms a protective interface layer while the conventional electrolyte maintains bulk ion conductivity, achieving both electrode protection and acceptable power output without the trade-off
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 solution improves life cycle characteristics and power output of lithium secondary batteries by forming protective layers, maintaining high-temperature stability and optimizing room-temperature performance without excessive cell resistance.
Implementation Method 1
the functional additive includes 4-((tert-butoxydimethylsilyl)methyl)-5-methyl-1,3-dioxol-2-one represented by Formula 1 as an electrode film additive
Implementation Method 2
an electrolyte being a lithium-ion transport medium
Implementation Method 3
Due to the change in chemical potential caused by the intercalation and deintercalation of lithium ions at the positive electrode and the negative electrode, electrical energy can be produced and stored
Data Source
AI summary
An embodiment electrolyte solution includes a lithium salt, a solvent, and a functional additive, wherein the functional additive includes 4-((tert-butoxydimethylsilyl)methyl)-5-methyl-1,3-dioxol-2-one represented byas an electrode film additive. An embodiment lithium secondary battery includes the above-described electrolyte solution, a positive electrode including a positive electrode active material including Ni, Co, and Mn, a negative electrode including a carbon-based negative electrode active material or a silicon-based negative electrode active material, and a separator interposed between the positive electrode and the negative electrode.