Conductive Cathode Coating for Li-Ion Salt Corrosion Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium-ion batteries face challenges in reducing impedance and heat production, particularly in high-power applications, where fluorine-containing sulfonimide lithium salts can cause corrosion on current collectors and affect long-term stability and high-rate cycling performance.
Innovation Solution
Incorporating a conductive coating between the positive electrode current collector and active substance layer, combined with fluorine-containing sulfonimide lithium salts in the electrolyte, to improve conductivity and reduce corrosion risk, while adding a second fluorine-containing metal salt to form a protective layer and using additives like sultone or cyclic carbonate to enhance stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If fluorine-containing sulfonimide lithium salts are used in the electrolyte, then conductivity of the electrolyte is improved, but corrosion on the current collector increases
Solution Approach 1:
A conductive coating layer is introduced as an intermediary between the fluorine-containing sulfonimide lithium salt electrolyte and the current collector. This coating prevents direct contact between the corrosive electrolyte and the current collector surface, thereby eliminating corrosion while maintaining electrolyte conductivity for high-rate cycling performance.
2Reliability
If a conductive coating is added between the current collector and active substance layer, then contact resistance is reduced and corrosion risk is reduced, but device complexity increases
Solution Approach 1:
The positive electrode is segmented into three distinct functional layers: the current collector, the conductive coating layer, and the active substance layer. This segmentation allows each layer to perform its specific function independently, with the conductive coating serving as a dedicated interface layer that reduces both contact resistance and corrosion risk.
3Use of energy by moving object
If the mass per unit area of fluorine-containing sulfonimide lithium salt is increased, then electrolyte conductivity is improved, but corrosion on the current collector increases
Solution Approach 1:
The conductive coating acts as a protective intermediary that decouples the relationship between electrolyte concentration and corrosion. This allows the use of high concentrations of fluorine-containing sulfonimide lithium salts to achieve excellent conductivity and high-rate cycling performance without suffering from increased corrosion, as the coating prevents direct interaction between the electrolyte and current collector.
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
This configuration enhances high-rate cycling performance, reduces temperature rise, and improves long-term stability by minimizing corrosion and heat production, thereby optimizing the performance of lithium-ion batteries in high-power applications.
Implementation Method 1
The conductive coating is introduced to reduce contact resistance between the current collector and an active material
Implementation Method 2
The fluorine-containing sulfonimide lithium salts provide good dissociation to improve conductivity of the electrolyte
Implementation Method 3
reduce, to a specific extent, a risk of corrosion caused by the fluorine-containing sulfonimide lithium salt being in contact with the current collector
Implementation Method 4
reduce temperature rise of the electrochemical apparatus
Data Source
AI summary
An electrochemical apparatus includes a positive electrode, a negative electrode, a separator, and an electrolyte, where the positive electrode includes a positive electrode current collector, a positive electrode active substance layer, and a conductive coating disposed between the positive electrode current collector and the positive electrode active substance layer; the electrolyte includes a first fluorine-containing metal salt, where the first fluorine-containing metal salt includes at least one of fluorine-containing sulfonimide lithium salts; and the electrochemical apparatus satisfies the following relationship: 0.1≤X/d≤105, where X g/m2 is mass per unit area of fluorine-containing sulfonimide lithium salt contained in the electrochemical apparatus on one surface of the positive electrode current collector, and d μm is thickness of the conductive coating on one surface of the positive electrode current collector.