Annealed Lithium-Philic Copper Current Collector for Even Li Deposition
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Solution Overview
Problem
The surface of the negative electrode current collector in lithium metal batteries is prone to detachment during cycling, leading to instability and uneven lithium deposition, which threatens the performance and safety of the battery.
Innovation Solution
A method involving the preparation of a lithium-philic plating film on a copper substrate followed by an annealing treatment at a controlled temperature, enhancing the bonding force between the plating layer and the substrate, and using specific gas atmospheres to reduce oxidation and improve uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lithium-philic plating layer is provided on the negative electrode current collector to facilitate lithium metal deposition, then the lithium deposition performance is improved, but the plating layer easily falls off during cycling which threatens battery performance
Solution Approach 1:
The patent applies annealing treatment at specific temperature ranges (200-800°C for Sn, 500-1000°C for Mg/Zn, 450-650°C for Bi, 600-800°C for Pb, 900-1100°C for Au, 800-1000°C for Ag, 600-700°C for Al) to modify the physical and chemical properties of the plating layer and substrate interface. This thermal treatment enhances the bonding strength between the plating layer and copper substrate while preserving the lithium-philic characteristics, thereby resolving the contradiction between deposition performance and bonding strength
Solution Approach 2:
The patent creates a composite structure consisting of a copper substrate with a lithium-philic metal plating layer (Sn, Mg, Zn, Bi, Pb, Au, Ag, or Al). This composite material system combines the high conductivity and structural stability of copper with the lithium-affinity of the plating metal, achieving both strong bonding and effective lithium deposition
2Loss of energy
If the plating layer is made thinner to reduce resistance, then the electrical conductivity is improved, but the plating layer becomes more prone to detachment during cycling
Solution Approach 1:
The annealing treatment modifies the microstructure and adhesion properties of thin plating layers, enabling them to maintain strong bonding to the substrate even at reduced thicknesses. The thermal processing optimizes the interface between the plating layer and copper substrate, allowing thin layers to resist detachment while preserving low electrical resistance
3Strength
If the annealing temperature is increased to enhance bonding strength, then the plating layer-substrate adhesion is improved, but the oxidation of the current collector and plating film increases
Solution Approach 1:
The patent specifies conducting annealing treatment in inert or reducing atmospheres including nitrogen, argon, nitrogen-hydrogen mixed gas, or mixed gas of inert gas and hydrogen (1-2% H2). This controlled atmosphere prevents oxidation of the copper substrate and lithium-philic metal plating layer during high-temperature annealing, allowing adhesion strength to be enhanced without oxidation damage
Solution Approach 2:
The inert or reducing gas atmosphere acts as a protective intermediary between the plating layer/substrate and oxygen. This gaseous environment shields the materials from oxidation during annealing while permitting the thermal bonding process to proceed effectively
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 method results in a stable negative electrode current collector that prevents detachment and promotes even lithium deposition, improving the cycling performance and safety of lithium metal batteries.
Implementation Method 1
subjecting the copper substrate prepared with the plating film to an annealing treatment at a preset temperature T to obtain the negative electrode current collector
Implementation Method 2
subjecting the copper substrate prepared with the plating film to an annealing treatment at a preset temperature T
Implementation Method 3
subjecting the copper substrate prepared with the plating film to an annealing treatment at a preset temperature T
Implementation Method 4
the possibility of oxidation of the current collector and the plating film can be effectively reduced
Data Source
AI summary
A negative electrode current collector and a preparation method therefor, a negative electrode plate, a lithium metal battery, and an electrical apparatus. The negative electrode current collector comprises a copper substrate and a plating layer arranged on the copper substrate, wherein the plating layer comprises a lithium-philic metal and a lithium-philic metal-copper alloy.