Separator Carbon Coating for Lithium Dendrite Suppression
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Solution Overview
Problem
Lithium-ion secondary batteries face challenges with lithium dendrite growth due to repeated charging and discharging, leading to internal short circuits and reduced reliability, especially at low temperatures.
Innovation Solution
A novel structure is introduced where a carbon layer is applied to one surface of a separator, which faces the negative electrode, to control the growth direction of dendrites, thereby inhibiting internal short circuits and enhancing battery reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separator is used in a lithium-ion secondary battery, then the battery can operate, but lithium dendrites grow and cause internal short circuits reducing reliability
Solution Approach 1:
A carbon layer is introduced as an intermediary substance between the separator and the negative electrode. This carbon layer serves as a mediator that dendrites must penetrate to reach the separator, thereby providing an additional protective barrier that enhances battery reliability without preventing normal lithium ion transport.
Solution Approach 2:
The carbon layer is applied in advance to the separator surface before battery operation begins. This pre-established protective layer acts as a cushioning barrier that dendrites must overcome, providing beforehand protection against the harmful effects of dendrite growth during charging and discharging cycles.
2Ease of operation
If graphite is used as negative electrode active material, then the battery can charge and discharge, but lithium dendrites are likely to deposit especially at low temperatures
Solution Approach 1:
The carbon layer acts as an intermediary between the graphite negative electrode and the electrolyte/separator interface. This intermediate carbon surface modifies the deposition behavior of lithium, making dendrite formation less likely during charging operations while maintaining normal charge-discharge functionality.
3Quantity of substance
If lithium metal is used instead of graphite, then battery capacity increases, but lithium dendrites deposit even at room temperature
Solution Approach 1:
The carbon layer serves as a critical intermediary that modifies the surface properties where lithium metal contacts the electrolyte and separator. This intermediate layer reduces the direct interaction that leads to dendrite formation, enabling lithium metal to maintain both high capacity and improved dendrite resistance.
Solution Approach 2:
The carbon coating is applied beforehand to the separator surface that will contact lithium metal. This pre-established protective barrier cushions against the inherently dendrite-prone nature of lithium metal deposition, allowing high capacity operation with reduced dendrite risk even at room temperature.
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 carbon layer effectively prevents dendrite growth from reaching the positive electrode, reducing the likelihood of internal short circuits and improving the overall reliability and performance of the secondary battery across various temperature conditions.
Implementation Method 1
control the growth direction of a dendrite deposited on a negative electrode
Implementation Method 2
drying the slurry to remove the solvent
Data Source
AI summary
To provide a method for manufacturing a secondary battery in which an internal short circuit due to a dendrite is inhibited. In a method for manufacturing a secondary battery, a separator is coated with slurry including carbon, a solvent, and a binder, a carbon layer including the binder is formed by drying the slurry to remove the solvent; and pressing is performed on the carbon layer and a negative electrode that face each other. Heating is preferably performed in the pressing.