Lithium Battery Electrolyte Composite Additives for High-Temperature Storage
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Solution Overview
Problem
Rechargeable lithium batteries face challenges in maintaining storage characteristics at high temperatures without deteriorating capacity and room temperature cycle-life, particularly in both state of charge and state of discharge, with existing additives often compromising battery performance.
Innovation Solution
An electrolyte solution comprising a lithium salt, non-aqueous organic solvent, fluoroethylene carbonate, vinyl-containing carbonate, cyclic sulfate, and a nitrile-based compound, with specific weight percentages to enhance storage characteristics at high temperatures without degrading capacity or cycle-life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional additives are used to improve storage characteristics at high temperature, then storage stability is improved, but battery capacity and room temperature cycle-life deteriorate
Solution Approach 1:
The patent employs a composite additive system comprising four specific components: fluoroethylene carbonate (1-7 wt%), vinylene carbonate (0.1-3 wt%), 1,3-propanesultone (0.1-10 wt%), and succinonitrile (0.1-10 wt%). This multi-component composite approach allows each additive to contribute different protective functions, achieving high-temperature storage stability while preserving battery capacity and cycle-life through synergistic effects among the components.
Solution Approach 2:
The patent optimizes the concentration parameters of each additive component within specific ranges to achieve the desired balance. By controlling the weight percentages of fluoroethylene carbonate (1-7%), vinylene carbonate (0.1-3%), 1,3-propanesultone (0.1-10%), and succinonitrile (0.1-10%), the formulation achieves optimal performance where storage stability is improved without compromising capacity and cycle-life.
2Stability of the object's composition
If electrolyte composition is modified to enhance high temperature storage, then storage characteristics improve, but performance in state of charge and state of discharge deteriorates
Solution Approach 1:
The patent uses a composite electrolyte system combining four specific additives in defined proportions. This composite approach enables the electrolyte to provide high-temperature storage stability while maintaining excellent performance in both charged and discharged states, as each component contributes complementary functions that do not interfere with electrochemical performance.
Solution Approach 2:
The patent creates different functional zones within the electrolyte system by assigning specific roles to different additives. Fluoroethylene carbonate and vinylene carbonate primarily protect the electrode surfaces, while 1,3-propanesultone and succinonitrile provide bulk electrolyte stability. This localized functional distribution allows high-temperature storage protection without compromising electrochemical performance.
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 solution effectively maintains excellent storage characteristics at high temperatures in both state of charge and state of discharge, while preserving battery capacity and cycle-life, as demonstrated by the rechargeable lithium battery cells' performance in various examples.
Implementation Method 1
a nitrile-based compound which forms films at a relatively low potential
Implementation Method 2
a positive electrode including a positive active material that can intercalate and deintercalate lithium, and including a negative electrode including a negative active material that can intercalate and deintercalate lithium
Implementation Method 3
an additive including fluoroethylene carbonate, a vinyl-containing carbonate, a substituted or unsubstituted C2 to C10 cyclic sulfate, and a nitrile-based compound
Data Source
AI summary
An electrolyte solution for a rechargeable lithium battery, including a lithium salt, a non-aqueous organic solvent, and an additive including fluoroethylene carbonate, a vinyl-containing carbonate, a substituted or unsubstituted C2 to C10 cyclic sulfate, and a nitrile-based compound represented by the following Chemical Formula 1:wherein, in Chemical Formula 1, R may be a substituted or unsubstituted C1 to C20 alkylene group.