Electrolyte Additive Composition for High-Voltage Cycle Stability
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Solution Overview
Problem
High-voltage electrochemical devices face challenges in maintaining energy density due to the oxidation activity of positive active materials, which can decompose the electrolytic solution and deteriorate the electrochemical material.
Innovation Solution
The electrolytic solution includes propylene carbonate, a compound represented by Formula I, and a compound represented by Formula II, which are added to improve intermittent cycle performance and suppress voltage drops after high-temperature storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional electrolytes are used in high-voltage electrochemical devices, then the device can operate at high voltage, but the electrolytic solution decomposes due to oxidation activity of positive active materials
Solution Approach 1:
The patent introduces a fluorinated cyclic carbonate compound as an intermediary substance that mediates between the high-voltage positive active material and the electrolytic solution. This compound forms a protective interface layer that prevents direct contact and oxidation reactions, allowing high-voltage operation while maintaining electrolyte stability.
Solution Approach 2:
The electrolytic solution uses a composite formulation combining fluorinated cyclic carbonate with other carbonate solvents and lithium salts. This composite electrolyte system leverages the oxidative stability of the fluorinated component while maintaining the ionic conductivity provided by the composite mixture, enabling both high voltage operation and electrolyte stability.
2Reliability
If the electrolytic solution is stabilized to prevent decomposition, then the device reliability improves, but the energy density decreases
Solution Approach 1:
The patent modifies the chemical parameters of the electrolytic solution by incorporating fluorinated cyclic carbonate compounds with specific molecular structures and ratios. This parameter change increases the oxidation potential threshold of the electrolyte, allowing it to remain stable at higher voltages without requiring excessive amounts of stabilizing additives, thus preserving energy density.
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 solution effectively enhances the intermittent cycle performance and reduces voltage drops in electrochemical devices, thereby increasing energy density under high voltage conditions.
Implementation Method 1
By the DFEC, a passivation film which is stable enough can be formed on the surface of a graphite material
Implementation Method 2
an electrolytic solution is critical to performance of the electrochemical device
Implementation Method 3
improve intermittent cycle performance and suppress voltage drops after high-temperature storage
Data Source
AI summary
This disclosure provides an electrolytic solution, an electrochemical device including the electrolytic solution, and an electronic device including the electrochemical device. The electrolytic solution includes a first additive, and the first additive includes propylene carbonate, a compound represented by Formula I, and a compound represented by Formula II. The electrolytic solution is applicable in the electrochemical device to effectively improve intermittent cycle performance of the electrochemical device and effectively suppress a voltage drop of the electrochemical device after high-temperature storage.