Cyclic Sulfone Electrolyte Additives for High-Voltage Li-Ion Cathode Stability
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Solution Overview
Problem
Li-ion batteries face challenges with cathode material stability at high potentials, leading to electrochemical oxidation, structural breakdown, and increased interfacial resistance, especially at extreme temperatures, necessitating improved electrolyte components for high-voltage and high-energy applications.
Innovation Solution
Incorporation of cyclic sulfone organic compounds as additives in the electrolyte, forming a stable SEI film on the anode and a unique CEI on the cathode, which enhances stability and reduces oxidative decomposition, thereby improving cycle life and high-temperature performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If carbonate-based electrolytes are used to transport lithium ions, then ion conductivity is improved, but cathode material stability deteriorates at high potentials due to oxidation
Solution Approach 1:
The patent introduces cyclic sulfone additives as intermediary substances that mediate between the carbonate-based electrolyte and the cathode material. These additives preferentially oxidize to form a stable CEI layer that acts as a protective barrier, preventing direct contact and further oxidation between the electrolyte and cathode material at high potentials, thus maintaining both ion conductivity and cathode stability
Solution Approach 2:
The patent modifies the chemical composition parameters of the electrolyte by incorporating cyclic sulfone compounds with specific molecular structures containing sulfur and oxygen atoms. This parameter change enables the formation of a cathode electrolyte interface (CEI) layer with different electrochemical stability characteristics, allowing the system to operate at higher potentials without cathode decomposition
2Use of energy by moving object
If high voltage cathode materials are used to increase energy density, then energy storage capability is improved, but electrolyte oxidation and cathode dissolution worsen
Solution Approach 1:
The patent converts the harmful oxidation reaction between the electrolyte and high-voltage cathode material into a beneficial process by controlling the initial oxidation of cyclic sulfone additives. This controlled oxidation forms a protective CEI layer that prevents further harmful reactions, effectively transforming the potential harm of oxidation into a protective mechanism that enables high-voltage operation
Solution Approach 2:
The patent creates a composite interface structure consisting of the cathode material and the cyclic sulfone-derived CEI layer. This composite structure combines the high energy density properties of advanced cathode materials with the electrochemical stability of the sulfone-based interface layer, enabling both high energy storage and reduced degradation
3Reliability
If conventional electrolyte additives are used to form SEI on anode, then anode protection is improved, but cathode stabilization at high temperatures worsens
Solution Approach 1:
The patent employs cyclic sulfone additives that perform multiple functions simultaneously: they form protective SEI on the anode through controlled reduction, stabilize the cathode through CEI formation via oxidation, and maintain thermal stability at elevated temperatures. This multi-functional additive replaces the need for separate additives for each protection mechanism
4Reliability
If formation cycle is extended to create stable SEI, then anode stability is improved, but manufacturing time increases
Solution Approach 1:
The cyclic sulfone additive performs preliminary action by forming a stable SEI layer during the initial formation cycle at lower voltages before full cell operation begins. This preliminary SEI formation prevents subsequent electrolyte decomposition and maintains anode stability throughout extended cycling, eliminating the need for prolonged formation periods
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 sulfone additives facilitate the formation of robust protective films on the anode and cathode, ensuring safe, long cycle life and high energy storage capabilities in lithium-ion batteries.
Implementation Method 1
Molecules with these functional groups as electrolyte additives allow for the formation of a robust SEI during the formation cycle that protects the anode
Implementation Method 2
The functional groups in the molecular structure also protect the cathode from decomposition at high temperatures and voltages
Implementation Method 3
The shuttling of positive and negative ions between the battery electrodes is the main function of the electrolyte
Data Source
AI summary
Cyclic sulfone organic compounds and an electrolyte containing the cyclic sulfone organic compounds suitable for use in electrochemical energy storage devices useful for reducing battery resistance, increasing cycle life, and improving high-temperature performance are disclosed.