Cyclic Sulfonate Electrolyte Additive for High-Temperature LIB Cycling
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Solution Overview
Problem
Lithium-ion batteries (LIBs) with carbon or lithium-based anode materials face reduced cycling performance and capacity due to solvent decomposition and gas production, especially at high temperatures, which hinders electrochemical reactions and battery durability.
Innovation Solution
A cyclic sulfonate additive is introduced into the electrolyte, specifically synthesized through a method involving sodium sulfite and sodium bisulfite reactions, to form a stable solid electrolyte interface (SEI) that inhibits solvent decomposition and gas production, improving battery performance by enhancing ion conductivity and reducing electron conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a non-aqueous electrolyte is used in LIBs with carbon or lithium-based anode materials, then the battery can operate with high initial capacity, but the solvent decomposes and produces gas during cycling, reducing cycling performance and capacity
Solution Approach 1:
The cyclic sulfonate additive performs preliminary action by forming a stable SEI film on the anode surface before the solvent can decompose. This pre-formed protective layer prevents subsequent solvent reduction and gas production during cycling, thereby maintaining both initial capacity and long-term cycling performance
Solution Approach 2:
The cyclic sulfonate additive acts as an intermediary substance between the electrode and the non-aqueous solvent. It forms an intermediate SEI layer that mediates the interaction, allowing ion transport while blocking direct contact between the solvent and electrode, thus preventing decomposition reactions
2Power
If a non-aqueous solvent is used in the electrolyte, then the battery achieves good electrochemical performance, but the solvent is oxidized and decomposed at the cathode interface at high temperatures, producing gas and reducing cycling performance
Solution Approach 1:
The cyclic sulfonate additive applies preliminary anti-action by forming a protective SEI layer that counteracts the oxidative decomposition of the solvent at the cathode interface. This pre-formed barrier prevents the harmful oxidation reaction from occurring, even at elevated temperatures
Solution Approach 2:
The invention converts the potentially harmful solvent decomposition reaction into a beneficial process by guiding the cyclic sulfonate additive to decompose first, forming a stable SEI layer. This transforms the harmful effect of solvent decomposition into a protective mechanism that prevents further degradation
3Reliability
If conventional additives are used to form SEI film, then solvent decomposition is inhibited to some extent, but the SEI film stability and ion conductivity are insufficient, leading to continued capacity fade
Solution Approach 1:
The invention applies parameter changes by modifying the chemical structure of the additive with specific R1 and R2 substituents (hydrogen, fluorine, phenyl, alkyl, or fluorine-containing alkyl) and controlling the ring size (n=1 or 2). These structural parameters optimize the SEI film's stability and ion conductivity, preventing capacity fade while maintaining 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 cyclic sulfonate additive significantly improves battery capacity retention and thermal stability, maintaining high capacity and reducing volume changes during high-temperature cycling, outperforming batteries without the additive and those using commercial additives in terms of capacity retention and thermal stability.
Implementation Method 1
form a stable long-term solid electrolyte interface (SEI) with high ion conductivity and low electron conductivity
Implementation Method 2
high ion conductivity
Implementation Method 3
low electron conductivity
Implementation Method 4
inhibiting a decomposition reaction of a solvent on a negative electrode
Implementation Method 5
a non-aqueous solvent in a non-aqueous electrolyte will be partially oxidized and decomposed locally at an interface between the cathode material and the non-aqueous electrolyte
Data Source
AI summary
A cyclic sulfonate additive for an electrolyte of a lithium-ion battery (LIB) is disclosed, with a structure shown in formula I:A non-aqueous electrolyte of a LIB can be prepared with the cyclic sulfonate additive for the electrolyte of the LIB as one of additives, together with a non-aqueous solvent, and an electrolyte lithium salt, and arranged between a negative electrode and a positive electrode to fabricate a LIB. The present disclosure provides a use of the cyclic sulfonate additive in a LIB, which can effectively inhibit the reduction of battery capacity during high-temperature cycling and high-temperature storage, and can also inhibit the decomposition of an electrolyte to produce a gas.