Layer Composite Electrode for Lithium Plating Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium ion battery systems with metallic lithium anodes face issues such as inhomogeneous lithium plating and stripping, leading to dendrite formation, electrolyte depletion, and reduced battery performance and cycle life, due to non-uniform current distribution and low electronic conductivity of electroactive materials, which are exacerbated by the surface roughness and particulate structure of the cathode.
Innovation Solution
A layer composite electrode structure is introduced, comprising a current collector, a base layer with particulate electroactive material, and a portion with a functional material having a different structure, which reduces surface roughness and improves electronic conductivity, ensuring even lithium plating and stripping by optimizing the morphology and current distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a cathode with particulate electroactive material is used, then the electrode structure is simple and easy to manufacture, but the surface roughness increases leading to non-uniform current distribution
Solution Approach 1:
The patent applies composite materials by combining particulate electroactive material with flake-shaped electroactive material in a layered structure. The base layer contains particulate material for ease of manufacture, while the overlaying layer contains flake-shaped material that fills surface irregularities and provides a smoother external surface, thus reducing surface roughness while maintaining manufacturing simplicity.
Solution Approach 2:
The patent implements local quality by creating different layers with different material shapes and properties. The base layer uses particulate material for manufacturing ease, while the top layer uses flake-shaped material specifically to address surface roughness issues. Each layer performs its local function optimally, with the flake-shaped layer specifically targeting the surface quality problem.
2Device complexity
If larger particle size electroactive material is used, then the electrode structure is simpler, but the electronic conductivity decreases leading to non-uniform current distribution
Solution Approach 1:
The patent uses composite materials combining larger particulate electroactive material in the base layer with smaller flake-shaped electroactive material in the overlaying layer. The flake-shaped material provides better electronic conductivity and fills conductivity gaps, while the larger particulate material maintains structural simplicity. This composite approach resolves the contradiction between device simplicity and electrical reliability.
Solution Approach 2:
The patent applies local quality by placing flake-shaped electroactive material specifically in the overlaying layer where it can address electronic conductivity issues at the surface level. The base layer retains larger particulate material for structural simplicity, while the top layer locally enhances conductivity where it is most needed for uniform current distribution.
3Manufacturing precision
If smaller particle size electroactive material is used, then the surface roughness decreases, but the cycle life decreases due to high surface area to volume ratio
Solution Approach 1:
The patent implements local quality by using smaller flake-shaped particles only in the overlaying layer to reduce surface roughness, while the base layer contains larger particulate material that provides structural stability and longer cycle life. This localized application of small particles minimizes their negative impact on cycle life while achieving the desired surface smoothness.
Solution Approach 2:
The patent uses composite materials where the base layer with larger particles provides long-term structural stability and cycle life, while the overlaying layer with smaller flake-shaped particles provides surface smoothness. The composite structure allows each material to perform its strength - the larger particles for durability and smaller particles for surface quality.
4Quantity of substance
If metallic lithium anode is used, then the energy density increases, but dendrite formation occurs due to inhomogeneous lithium plating and stripping
Solution Approach 1:
The patent applies local quality by creating a cathode structure where the overlaying layer with flake-shaped material locally modifies the current distribution at the electrode surface. This creates more uniform current density across the electrode area, which translates to more uniform lithium plating and stripping at the anode, preventing dendrite formation while maintaining the high energy density benefits of metallic lithium anodes.
Solution Approach 2:
The patent uses composite materials in the cathode structure to achieve uniform current distribution that prevents anode dendrites. The combination of particulate and flake-shaped electroactive materials creates a cathode with optimized electrical properties that ensure homogeneous lithium extraction during charging, which in turn prevents inhomogeneous lithium deposition and dendrite formation on the metallic lithium anode.
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 layer composite electrode achieves improved uniformity in lithium plating and stripping, enhanced cycle life, and maintained rate capability, while reducing the risk of dendrite formation and mechanical damage to the protective layer, thus improving the overall performance and reliability of lithium ion batteries.
Implementation Method 1
improves electronic conductivity, ensuring even lithium plating and stripping by optimizing the morphology and current distribution
Data Source
Figure 1A~1D
Figure 1B~1C
Figure 2
AI summary
The present invention relates to a layer composite, an electrode comprising or consisting of said layer composite, an electrochemical cell comprising said electrode and a method for forming said layer composite.