Carbonate-Modified Siloxane Electrolyte Additives for Battery Thermal Stability
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Solution Overview
Problem
Lithium ion secondary batteries and electric double-layer capacitors face issues with discharge characteristics, especially in low-temperature environments and high-output conditions, and suffer from insufficient withstand voltages and capacity decline over time, with existing non-aqueous electrolytic solutions posing safety risks due to thermal instability and high melting points.
Innovation Solution
A non-aqueous electrolytic solution comprising a carbonate-modified silane and/or siloxane, specifically formulated with certain chemical structures and reaction processes, is used to enhance charge/discharge characteristics and safety, incorporating a solvent, electrolyte salt, and carbonate-modified silanes or siloxanes to improve compatibility and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyether-modified siloxanes are added to improve wetting and charge/discharge cycle performance, then charge/discharge cycle performance is improved, but thermal stability is insufficient and melting point is relatively high causing problems during low-temperature service
Solution Approach 1:
The patent modifies the chemical structure of siloxanes by introducing carbonate groups at specific positions (using formulas (1) and (2) with defined parameters a, b, x and groups R1, R2, R3, A). This structural parameter change reduces the melting point from 70°C or higher (polyether-modified siloxanes) to below 0°C (carbonate-modified siloxanes) while maintaining charge/discharge cycle performance improvement capabilities
Solution Approach 2:
The patent creates composite molecular structures by combining siloxane backbones with carbonate functional groups. The carbonate-modified siloxanes (formulas (1) and (2)) integrate the electrochemical benefits of siloxanes with the thermal properties of carbonate groups, achieving both low melting point and high thermal stability
2Use of energy by moving object
If non-aqueous electrolytic solutions based on low-flash-point solvents are used to achieve high energy density, then energy density is improved, but thermal runaway risk increases causing battery rupture and ignition
Solution Approach 1:
The patent converts the potential harm of thermal runaway into a benefit by using carbonate-modified siloxanes that form stable surface films on electrodes. These films act as protective barriers that prevent further decomposition reactions, effectively converting the thermal energy that would cause runaway into a stabilizing effect through controlled surface passivation
Solution Approach 2:
The carbonate-modified siloxanes act as intermediary substances between the electrolyte and electrode surfaces. They form interfacial films that mediate the interaction, preventing direct contact between the low-flash-point electrolyte and hot electrode surfaces, thus blocking the thermal runaway pathway while maintaining ionic conductivity
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 effectively improves charge/discharge characteristics and safety of energy devices, such as batteries and capacitors, by enhancing electrolyte dissolution, ion mobility, and thermal stability, while reducing the risk of thermal runaway and improving cycle performance.
Implementation Method 1
The non-aqueous electrolytic solution is effective for improving charge/discharge characteristics and able to dissolve electrolyte salts therein
Data Source
AI summary
A carbonate-modified silane or siloxane is combined with a non-aqueous solvent and an electrolyte salt to form a non-aqueous electrolytic solution, which is used to construct a secondary battery having improved charge/discharge characteristics.