Multi-Protective Layer for Lithium Metal Negative Electrode
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Solution Overview
Problem
Lithium secondary batteries face issues with lithium dendrite growth on the negative electrode surface, leading to cell volume expansion, performance decline, and potential battery explosion due to the rough electrode surface and internal short circuits.
Innovation Solution
A multi-protective layer structure is applied to the lithium metal negative electrode, comprising a first protective layer with high ion conductivity and liquid electrolyte uptake, a second protective layer with strong physical strength and ion conductivity for dendrite suppression, and a third protective layer for structural support, all of which are formed using specific polymers and inorganic compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single protective layer is used on the lithium metal negative electrode, then the structure is simple and easy to manufacture, but it cannot effectively suppress lithium dendrite growth and maintain long-term stability
Solution Approach 1:
The protective layer is divided into multiple sub-layers with distinct functions: a first protective layer for initial protection and interface formation, a second protective layer for enhanced dendrite suppression, and a third protective layer for structural support. This segmentation allows each layer to be optimized for its specific function, achieving superior overall performance compared to a single-layer structure.
Solution Approach 2:
The patent employs composite material structures where different protective layers are composed of materials with complementary properties. The combination of materials in the multi-layer structure creates synergistic effects that enhance dendrite suppression capability while maintaining ion conductivity and structural integrity.
2Quantity of substance
If lithium metal is used as the negative electrode material, then high capacity and low potential are achieved, but lithium dendrite formation occurs causing safety issues
Solution Approach 1:
The multi-layer protective structure acts as an intermediary between the lithium metal negative electrode and the electrolyte. This intermediary layer system allows the lithium metal to maintain its high capacity and low potential advantages while preventing direct contact and harmful interactions that lead to dendrite formation, thereby eliminating safety risks.
Solution Approach 2:
The protective layers are applied in advance to the lithium metal surface before dendrite formation can occur. This preliminary protective action prevents the harmful dendrite formation process from initiating, allowing the lithium metal to function at its full capacity without safety concerns throughout the battery's operational life.
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 multi-protective layer effectively suppresses lithium dendrite growth, maintains ion conductivity, and prevents overvoltage during charge and discharge, enhancing battery stability and performance, and extending the battery's lifespan.
Implementation Method 1
a first protective layer formed on the lithium metal layer and maintaining an interface with the lithium metal layer
Implementation Method 2
having high ion conductivity and liquid electrolyte uptake
Implementation Method 3
a second protective layer formed on the first protective layer and physically suppressing dendrite growth
Implementation Method 4
a third protective layer formed on the second protective layer and supporting a structure of the second protective layer
Implementation Method 5
The lithium secondary battery produces electric energy through an oxidation and reduction reaction occurring when lithium ions are intercaiated deintercaiated in the positive electrode and the negative electrode
Data Source
AI summary
The present invention relates to a negative electrode including a multi-protective layer and a lithium secondary battery including the same. The multi-protective layer is capable of effectively transferring lithium ions to a lithium metal electrode while physically suppressing lithium dendrite growth on the electrode surface, and does not cause an overvoltage during charge and discharge since the protective layer itself does not function as a resistive layer due to excellent ion conductivity of the multi-protective layer, and therefore, is capable of preventing battery performance decline and securing stability during battery operation.