Non-Aqueous Cell Electrolyte Using Imide Salt Protective Films
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Solution Overview
Problem
Non-aqueous electrolyte batteries face challenges in maintaining low-temperature characteristics and high-temperature storage characteristics, particularly in suppressing internal resistance increase at low temperatures and gas generation at high temperatures.
Innovation Solution
A non-aqueous electrolyte comprising a solvent and a solute with hexafluorophosphate and/or tetrafluoroborate, along with an imide anion-containing salt with specific structures, which forms a film to prevent decomposition and improve battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vinylene carbonate is added to suppress electrolyte decomposition on electrode surfaces, then high-temperature battery characteristics are improved, but internal resistance significantly increases and low-temperature characteristics deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by introducing a specific imide salt compound with particular molecular structure characteristics. This compound modifies the electrolyte's interaction with electrode surfaces, forming protective films with different properties than conventional additives, thereby reducing internal resistance while maintaining high-temperature stability.
Solution Approach 2:
The patent creates a composite electrolyte system by combining the imide salt compound with specific solvents (cyclic carbonates and chain carbonates) in defined ratios. This composite approach synergistically combines the film-forming properties of the imide salt with the solvation capabilities of the carbonate solvents, achieving both low-temperature conductivity and high-temperature stability.
2Object-generated harmful factors
If conventional electrolyte additives are used to improve high-temperature storage characteristics, then gas generation is suppressed, but low-temperature output characteristics and cycle characteristics remain insufficient
Solution Approach 1:
The patent modifies the electrolyte composition by incorporating the imide salt compound with specific structural parameters (as defined in the general formula), which changes the chemical behavior of the electrolyte across different temperature ranges. This compound suppresses gas-generating decomposition reactions at high temperatures while maintaining ionic conductivity at low temperatures.
Solution Approach 2:
The imide salt compound acts locally at the electrode-electrolyte interface, forming protective films that prevent electrolyte decomposition and gas generation. This localized action at the critical interface region suppresses harmful effects without significantly affecting the bulk electrolyte's ionic conductivity, thereby maintaining low-temperature performance.
3Duration of action of stationary object
If the electrolyte is optimized for high-temperature cycle characteristics, then deterioration during repeated charging and discharging is suppressed, but low-temperature internal resistance remains high
Solution Approach 1:
The patent adjusts the chemical composition parameters of the electrolyte by incorporating the imide salt compound in specific concentrations (0.01-5 wt%). This concentration optimization ensures sufficient film formation for cycle durability while maintaining adequate ionic conductivity for low-temperature operation.
Solution Approach 2:
The imide salt compound acts as an intermediary substance that mediates between the electrode surfaces and the bulk electrolyte. It forms interfacial protective layers that enhance cycle durability while allowing efficient ion transport, thereby resolving the contradiction between long-term stability and low-temperature 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 electrolyte effectively balances the suppression of internal resistance at low temperatures and gas generation at high temperatures, enhancing the battery's cycle and storage characteristics.
Implementation Method 1
an imide anion-containing salt with a specific structure, which forms a film to prevent decomposition and improve battery performance
Data Source
AI summary
Provided is an electrolyte for a non-aqueous electrolyte battery, which can provide, when used in a non-aqueous electrolyte battery, in a good balance, an effect to suppress an increase in an internal resistance at a low temperature and an effect to suppress an increase in an amount of gas generated at a high temperature, as well as a non-aqueous electrolyte battery containing such an electrolyte. The non-aqueous electrolyte comprises a non-aqueous solvent and at least a hexafluorophosphate and/or tetrafluoroborate as a solute, and further comprises at least one imide anion-containing salt represented by the following general formula [1] but does not contain a silane compound represented by the following general formula [2] or an ionic complex represented by, for example, the following general formula [3]. Si(R4)a(R4)4-a [2]