Non-Aqueous Electrolyte Blends for High-Voltage Li-Ion Safety
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Solution Overview
Problem
Current non-aqueous electrolytes in lithium-ion batteries face challenges with high-voltage and high-temperature performance, including poor oxidation resistance, easy decomposition, gas generation, low flash point, and safety hazards such as overcharge and hot box safety issues.
Innovation Solution
A non-aqueous electrolyte comprising a mixture of a carbonate solvent and a high oxidation potential solvent, with the high oxidation potential solvent making up 10% to 60% of the total solvent weight, which includes specific compounds characterized by fluorinated alkyl groups and alkylene chains, enhancing oxidation resistance and non-flammability while maintaining low viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional non-aqueous electrolytes using lithium hexafluorophosphate and cyclic/linear carbonate are used, then the battery system is simple and widely applicable, but the oxidation resistance is poor and decomposition occurs easily under high voltage and high temperature conditions
Solution Approach 1:
The patent employs a composite electrolyte system combining lithium hexafluorophosphate with multiple carbonate solvents (cyclic and linear) and introduces sulfone compounds as a key additive. This composite approach creates synergistic effects where the sulfone compound enhances oxidation resistance and stabilizes the electrolyte under high voltage conditions, while the mixture of carbonate solvents maintains low viscosity and good ion conductivity. The result is an electrolyte composition that achieves superior reliability without excessive complexity.
Solution Approach 2:
The patent optimizes specific parameters of the electrolyte composition, including the concentration of sulfone compound (0.1-10 wt%), the ratio of cyclic to linear carbonate solvents, and the overall composition proportions. By carefully adjusting these parameters, the electrolyte achieves optimal balance between oxidation resistance, viscosity, and conductivity, enabling high-voltage and high-temperature performance while maintaining practical applicability.
2Reliability
If conventional non-aqueous electrolytes are used, then the electrolyte formulation is simple, but safety performance including overcharge safety and hot box safety is insufficient
Solution Approach 1:
The patent creates a composite electrolyte formulation that integrates lithium hexafluorophosphate, multiple carbonate solvents, and sulfone compounds. This composite structure provides enhanced safety performance through synergistic mechanisms: the sulfone compound forms stable protective films on electrodes during overcharge conditions, preventing dangerous reactions, while the carbonate solvent mixture maintains fluidity and ion transport. The formulation also improves hot box safety by stabilizing the electrolyte against thermal decomposition.
Solution Approach 2:
The electrolyte formulation incorporates sulfone compounds that proactively form protective interface films on electrode surfaces before abnormal conditions occur. This preliminary protection layer acts as a cushion against overcharge damage and thermal runaway, preventing harmful reactions before they can initiate. The formulation is designed to anticipate and prevent safety issues rather than merely responding to them.
3Reliability
If the electrolyte uses high oxidation resistance compounds, then oxidation resistance and safety improve, but viscosity increases and kinetic performance deteriorates
Solution Approach 1:
The patent employs a composite solvent system that combines cyclic carbonate (higher dielectric constant) with linear carbonate (lower viscosity). This composite approach balances the competing requirements: the cyclic carbonate component contributes to oxidation resistance and electrode stabilization, while the linear carbonate component maintains low viscosity and high ion mobility. The addition of sulfone compounds further enhances oxidation resistance without significantly increasing viscosity, achieving an optimal balance between reliability and kinetic performance.
Solution Approach 2:
The patent carefully controls the concentration of sulfone compound (0.1-10 wt%) and the ratio of cyclic to linear carbonate solvents to optimize the balance between oxidation resistance and viscosity. By adjusting these parameters, the electrolyte achieves sufficient oxidation stability while maintaining adequate ion conductivity and kinetic performance for practical battery applications.
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 significantly improves electrochemical performance, safety, and kinetic performance of lithium-ion batteries under high temperature and high voltage conditions by combining the advantages of high oxidation resistance and non-flammability with low viscosity, thereby enhancing cycle life, storage life, and safety against overcharge and hot box hazards.
Implementation Method 1
the non-aqueous electrolyte can combine advantages of high oxidation resistance and non-flammability of high oxidation potential solvents
Implementation Method 2
combining the advantages of high oxidation resistance and non-flammability with low viscosity
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
This application provides a non-aqueous electrolyte, a lithium-ion battery, a battery module, a battery pack, and an apparatus. The non-aqueous solvent includes a non-aqueous solvent and a lithium slat. The non-aqueous solvent includes a carbonate solvent and a high oxidation potential solvent, and the high oxidation potential solvent is selected from one or more of compounds represented by formula I and formula II. Based on a total weight of the non-aqueous solvent, a weight percentage of the high oxidation potential solvent is 10% to 60%. This application can not only improve electrochemical performance of the lithium-ion battery under high temperature and high voltage and improve safety performance such as overcharge safety and hot box safety of the lithium-ion battery, but also ensure that the lithium-ion battery has some kinetic performance.