Sulfone Additive for Lithium Battery SEI Stability
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Solution Overview
Problem
Lithium batteries face challenges with irreversible side reactions and rapid degradation at high temperatures due to the formation of a thick solid electrolyte interface layer when using carbonate-based non-aqueous solvents, leading to reduced cycle lifetime characteristics.
Innovation Solution
Incorporating a sulfone compound with a sulfonyl group directly bonded to a halide group and an electron withdrawing group, such as an isocyanate group, as an electrolyte additive to form a stable and dense solid electrolyte interface layer, reducing self-reduction voltage and enhancing chemical reactivity with electrode components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If carbonate-based non-aqueous solvent is used in lithium battery, then high ionic conductivity and high dielectric constant are achieved, but irreversible side reactions occur during initial charging and thick SEI layer forms causing rapid capacity loss
Solution Approach 1:
The patent introduces a fluorinated cyclic carbonate compound as an intermediary substance that mediates between the electrode and the carbonate-based electrolyte solvent. This intermediary forms a stable protective interface layer that prevents direct harmful interactions between the electrolyte and electrode, thereby reducing irreversible side reactions and improving cycle lifetime while maintaining the high ionic conductivity of the carbonate-based solvent system
Solution Approach 2:
The patent modifies the chemical composition parameters of the electrolyte by incorporating fluorinated cyclic carbonate compounds with specific molecular structures (Formula 1 and Formula 2). This parameter change in the electrolyte composition alters the formation characteristics of the SEI layer, creating a thinner and more stable interface layer that reduces capacity loss while preserving the beneficial electrical properties of the carbonate-based solvent
2Power
If high operation temperature is applied to lithium battery, then high energy output is achieved, but severe electrolyte decomposition occurs and cycle lifetime deteriorates
Solution Approach 1:
The patent applies preliminary action by having the fluorinated cyclic carbonate compound react during the initial charging cycles to form a stable protective SEI layer before high-temperature operation begins. This pre-formed protective layer acts as a thermal barrier and chemical shield that prevents severe electrolyte decomposition during subsequent high-temperature operation, allowing the battery to maintain high energy output without rapid degradation
Solution Approach 2:
The patent converts the potentially harmful thermal and chemical energy that would otherwise cause electrolyte decomposition at high temperatures into a beneficial stable interface layer. The fluorinated cyclic carbonate compound undergoes controlled decomposition during initial cycles to form a thermally stable SEI layer, transforming what would be harmful decomposition into a protective mechanism that enhances cycle lifetime during high-temperature power delivery
3Ease of operation
If initial charging process occurs with carbonate-based solvent, then battery activation is achieved, but excessive charge consumption occurs due to irreversible side reactions
Solution Approach 1:
The fluorinated cyclic carbonate compound serves as an intermediary that facilitates battery activation while minimizing energy loss. During initial charging, this compound preferentially reacts to form a stable SEI layer, acting as a mediator that enables necessary electrochemical activation without the excessive charge consumption associated with conventional carbonate-based solvents alone
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 sulfone compound improves the high-temperature storage and lifetime characteristics of lithium batteries by forming a robust and stable solid electrolyte interface layer, reducing irreversible capacity and maintaining battery performance over repeated charging/discharging cycles.
Implementation Method 1
an irreversible side reaction between an anode and/or a cathode and the electrolytic solution may occur during an initial charging process
Implementation Method 2
form a thick solid electrolyte interface layer (also, referred to as an SEI layer) formed of decomposition products of electrolyte components on the surface of an electrode
Implementation Method 3
a sulfone compound wherein the sulfonyl group is directly bonded to a halide group and an electron withdrawing group
Data Source
AI summary
In an aspect, an electrolyte additive and an electrolyte for a lithium battery and a lithium battery including the electrolyte additive is provided. The electrolyte additive includes a sulfone compound wherein the sulfonyl group is directly bonded to a halide group and an electron withdrawing group.