Lithium Battery Electrolyte Additives for Low-Gas Cycle Stability
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Solution Overview
Problem
Rechargeable lithium batteries face challenges in maintaining high energy density and capacity while minimizing gas generation and resistance increase during cycling and high-temperature storage.
Innovation Solution
An electrolyte composition for lithium batteries comprising a non-aqueous organic solvent, lithium salt, and specific additives represented by Chemical Formulas 1 and 2, which suppress gas generation and resistance increase by controlling moisture and stabilizing transition metal ions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional electrolyte compositions are used to achieve high energy density and capacity, then battery capacity is improved, but gas generation and resistance increase during cycling and high-temperature storage worsen
Solution Approach 1:
The patent introduces a fluorinated cyclic carbonate additive as an intermediary substance that mediates between the electrolyte and electrode surfaces. This additive preferentially reacts to form stable protective films that prevent harmful side reactions, thereby suppressing gas generation and resistance increase while maintaining high battery capacity
Solution Approach 2:
The patent modifies the electrolyte composition by incorporating fluorinated cyclic carbonate with specific molecular structure parameters (fluorine substitution positions and ratios). These parameter changes in the additive's chemical structure enable it to form more stable solid electrolyte interphase (SEI) films, effectively reducing gas generation and resistance increase during cycling and storage
2Object-generated harmful factors
If electrolyte additives are increased to suppress gas generation and resistance increase, then suppression of harmful factors is improved, but room-temperature cycle-life characteristics worsen
Solution Approach 1:
The patent optimizes the concentration parameter of the fluorinated cyclic carbonate additive within a specific range (0.1-5 wt%). This parameter optimization ensures sufficient formation of protective films to suppress gas generation and resistance increase, while avoiding excessive additive consumption that would degrade room-temperature cycle-life characteristics
Solution Approach 2:
The patent creates a composite electrolyte system combining fluorinated cyclic carbonate additive with conventional electrolyte components (cyclic carbonates and chain carbonates). This composite formulation synergistically provides both protective film formation for suppressing harmful factors and maintained ionic conductivity for good room-temperature cycle-life characteristics
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 enhances room-temperature cycle-life characteristics and reduces gas generation and resistance increase, thereby improving the performance and stability of lithium batteries.
Implementation Method 1
controlling moisture and stabilizing transition metal ions
Implementation Method 2
controlling moisture and stabilizing transition metal ions
Implementation Method 3
lithium ions are intercalated and deintercalated
Implementation Method 4
The rechargeable lithium battery generates electrical energy caused by oxidation and reduction reactions
Data Source
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AI summary
An electrolyte for a rechargeable lithium battery and a rechargeable lithium battery including the electrolyte are disclosed. The electrolyte may include a nonaqueous (e.g., water-insoluble) organic solvent, a lithium salt, a first additive represented by Chemical Formula 1, and a second additive represented by Chemical Formula 2. A more detailed description of the first additive and the second additive is provided in the present disclosure.