Coated Separator Structure for High-Rate Lithium Dendrite Suppression
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Solution Overview
Problem
Lithium ion batteries face safety hazards due to the growth of lithium dendrites during high-rate charging and discharging, especially at low temperatures, leading to increased internal short circuits and reduced cycle life.
Innovation Solution
A separator is designed with a first porous substrate, a second porous substrate, and a first coating layer containing a substance that reversibly intercalates and deintercalates lithium, along with an electrochemically stable inorganic particle, to inhibit lithium dendrite growth and enhance safety, rate, and cycle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-rate charging and discharging is performed, then power output is improved, but lithium dendrite growth increases causing safety hazards
Solution Approach 1:
A coating layer comprising inorganic particles and a substance capable of reversibly intercalating and deintercalating lithium is applied to the porous substrate. This coating layer acts as an intermediary between the electrode and the separator, suppressing lithium dendrite growth while maintaining high-rate charge-discharge performance, thus resolving the contradiction between power output and safety
Solution Approach 2:
The separator is constructed as a composite material system combining a porous substrate with a coating layer containing both inorganic particles and lithium-intercalating substances. This composite structure provides both the mechanical support needed for high power output and the chemical functionality to prevent dendrite growth, ensuring safety during high-rate operation
2Loss of energy
If charging is performed at low temperature, then energy conservation is improved, but lithium precipitation and dendrite formation increase
Solution Approach 1:
The coating layer with lithium-intercalating substances serves as a mediator that facilitates lithium ion insertion/extraction at low temperatures. This prevents lithium precipitation and dendrite formation while maintaining energy conservation benefits of low-temperature charging
Solution Approach 2:
The coating layer modifies the electrochemical parameters at the electrode interface, enabling reversible lithium intercalation at lower temperatures. This changes the kinetic parameters to prevent lithium precipitation, allowing safe low-temperature charging that conserves energy
3Ease of manufacture
If the separator structure is simplified, then manufacturing cost is reduced, but ability to suppress lithium dendrites deteriorates
Solution Approach 1:
A porous substrate is used as the base structure of the separator, providing both mechanical support and ion transport pathways. The porous structure is cost-effective to manufacture while the added coating layer provides dendrite suppression functionality, balancing manufacturing ease with safety 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 separator effectively reduces the risk of lithium dendrite growth, improving the safety and performance of lithium ion batteries by preventing internal short circuits and extending cycle life.
Implementation Method 1
a first coating layer including a substance that reversibly intercalates and deintercalates lithium, and a first inorganic particle
Data Source
Figure 1~2
AI summary
The present application provides a separator comprising a first porous substrate, a second porous substrate and a first coating layer including a substance that reversibly intercalates and deintercalates lithium and a first inorganic particle, and an electrochemical device, wherein the first coating layer is disposed between the first porous substrate and the second porous substrate. By disposing the first coating layer between the first porous substrate and the second porous substrate, the present application improves the safety performance, rate performance and cycle performance of the electrochemical device.