Carbon Anode Coating for Li-Ion Cycle and Storage Stability
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Solution Overview
Problem
Lithium-ion batteries face performance deterioration due to the formation of pinholes and pits in the active material layer caused by bubbles in aqueous slurry compositions, leading to reduced cycling and high-temperature storage performance.
Innovation Solution
An electrochemical device with a carbon-based anode mixture layer incorporating a polymer compound with Si—C and Si—O bonds, along with a specific electrolyte composition, including propionate, organic compounds with cyano groups, or lithium difluorophosphate, to enhance interface stability and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If aqueous slurry composition is used to reduce environmental impact, then environmental friendliness is improved, but pinholes and pits form in the active material layer due to bubbles, worsening manufacturing precision and reliability
Solution Approach 1:
The patent extracts and removes bubbles from the aqueous slurry composition through a vacuum treatment process before coating. This eliminates the harmful bubbles that would otherwise create pinholes and pits in the active material layer, allowing the use of environmentally friendly aqueous slurries without compromising layer quality.
Solution Approach 2:
The patent applies a preliminary vacuum treatment to the aqueous slurry composition before the coating process. This preliminary removal of bubbles prevents the formation of defects during subsequent coating and drying operations, ensuring high manufacturing precision while maintaining environmental benefits.
2Reliability
If cycle performance is improved through material optimization, then reliability is improved, but interface stability deteriorates, worsening long-term performance
Solution Approach 1:
The patent introduces a polymer compound containing Si-C and Si-O bonds as an intermediary layer on the anode surface. This intermediary layer stabilizes the anode interface by preventing direct harmful interactions between the carbon material and electrolyte, while simultaneously improving cycle performance through enhanced interface stability.
Solution Approach 2:
The patent uses a composite polymer compound containing both Si-C and Si-O bonds. This composite material structure provides dual functionality: the Si-C bonds contribute to stability while the Si-O bonds enhance interface protection, thereby improving both cycle performance and interface stability simultaneously.
3Power
If power characteristics are enhanced through anode optimization, then productivity is improved, but safety performance deteriorates, worsening device reliability
Solution Approach 1:
The patent modifies the chemical composition parameters of the anode by incorporating a polymer compound with specific Si-C and Si-O bond ratios. This parameter change enhances power characteristics through improved ion transport while simultaneously improving safety performance through enhanced thermal and chemical stability of the anode structure.
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 solution improves cycle performance and high-temperature storage performance by stabilizing the anode interface and reducing defects in the anode mixture layer, leading to enhanced power and safety characteristics in lithium-ion batteries.
Implementation Method 1
at least a part of a surface of the anode mixture layer or a surface of the carbon material includes a polymer compound having Si—C and Si—O bonds
Implementation Method 2
a surface tension of an aqueous solution containing 0.1 wt % of the polymer compound having Si—C and Si—O bonds being not greater than 30 mN/m
Implementation Method 3
Lithium-ion batteries with high energy density and excellent service life and cycle performance
Data Source
AI summary
An electrochemical device, including a cathode; an anode; and an electrolyte. The anode has an anode mixture layer on an anode current collector, the anode mixture layer includes a carbon material as an anode active material, and at least a part of a surface of the anode mixture layer or a surface of the carbon material comprises a polymer compound having Si—C and Si—O bonds. The electrochemical device has improved cycle performance and storage performance.