3D Lithium Metal Anode Framework for Dendrite-Free Deposition
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Solution Overview
Problem
Lithium metal batteries face issues with lithium dendrites and dead lithium formation, leading to impaired Coulombic efficiency and cycle performance due to lithium deposition and volume expansion during charging and discharging.
Innovation Solution
A secondary battery design featuring a negative electrode plate with a three-dimensional framework composed of a first and second framework layer, including one-dimensional conductive fibers, zero-dimensional, and two-dimensional materials, which creates a lithiophilic gradient to facilitate lithium deposition from the bottom upward, reducing dendrite formation and enhancing cycle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium metal is used as the negative electrode material to achieve high energy density, then the gravimetric specific energy is improved, but lithium dendrites and dead lithium form during charging, impairing Coulombic efficiency and cycle performance
Solution Approach 1:
The patent applies local quality by creating a three-dimensional framework with spatially varying lithiophilic properties. The framework includes regions with different lithiophilic strengths arranged in a gradient pattern, where certain areas have stronger affinity for lithium ions than others. This spatial variation in local quality guides lithium deposition to occur preferentially in specific regions, preventing dendrite formation while maintaining high capacity utilization.
Solution Approach 2:
The three-dimensional framework acts as an intermediary structure between the lithium metal and the electrolyte. This framework mediates the lithium deposition process by providing a controlled interface that directs ion flow and deposition patterns. The framework's lithiophilic regions serve as intermediate zones that facilitate uniform lithium distribution, preventing direct uncontrolled deposition on lithium metal surfaces.
2Duration of action of moving object
If lithium metal expands and shrinks during charging and discharging, then the battery operates, but the solid electrolyte interface (SEI) film peels and fragments, impairing Coulombic efficiency
Solution Approach 1:
The patent employs a three-dimensional framework structure that can accommodate volume changes during lithium insertion and extraction. This framework acts as a flexible scaffold that maintains structural integrity while allowing for expansion and contraction. The framework's design includes sufficient porosity and mechanical compliance to absorb dimensional changes without causing SEI film failure.
Solution Approach 2:
The negative electrode is constructed as a composite structure combining the three-dimensional framework with lithiophilic materials. This composite design integrates the mechanical stability of the framework with the electrochemical activity of the lithiophilic components, creating a synergistic structure that maintains SEI film integrity while enabling reversible lithium storage.
3Quantity of substance
If lithium dendrites form during charging, then lithium deposition occurs, but the battery safety and performance deteriorate
Solution Approach 1:
The patent utilizes parameter changes by varying the lithiophilic properties across the three-dimensional framework. By controlling the distribution and concentration of lithiophilic materials within the framework, the patent creates a gradient in lithium affinity parameters. This parameter variation guides lithium ions to deposit uniformly across multiple sites rather than concentrating at single points, preventing dendrite formation while maintaining high deposition efficiency.
Solution Approach 2:
The patent transitions from two-dimensional surface deposition to three-dimensional volumetric deposition by implementing a three-dimensional framework structure. This dimensional change provides additional spatial pathways for lithium ion transport and deposition, distributing the deposition process throughout the framework's volume rather than confining it to a flat surface, thereby eliminating the conditions that lead to dendrite formation.
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 design improves Coulombic efficiency and cycle performance by controlling the thickness and composition of the framework layers, reducing lithium dendrite formation and volume expansion, thereby enhancing the battery's overall performance and safety.
Implementation Method 1
enable lithium metal to enter the interior of the three-dimensional framework and deposit from bottom upward
Implementation Method 2
The zero-dimensional material is a lithiophilic material... a lithiophilic gradient is favorably constructed
Data Source
Figure 1~2
Figure 3
AI summary
A secondary battery includes a negative electrode plate and a separator. The negative electrode plate includes a three-dimensional framework. The three-dimensional framework includes a first framework layer and a second framework layer. The first framework layer includes one-dimensional conductive fibers. The second framework layer includes a zero-dimensional material, a one-dimensional material, and a two-dimensional material. The zero-dimensional material is a lithiophilic material. By adjusting and controlling the thicknesses of the three-dimensional framework, the first framework layer, and the second framework layer, the mass percent of the zero-dimensional material, and the mass ratio between the one-dimensional material and the two-dimensional material to fall within the ranges specified herein, a lithiophilic gradient is favorably constructed in the three-dimensional framework, so as to enable lithium metal to enter the interior of the three-dimensional framework and deposit from bottom upward, thereby improving the Coulombic efficiency and cycle performance of the secondary battery.