Polymer-Coated Lithium Powder Electrode Manufacturing
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Solution Overview
Problem
Existing methods for manufacturing lithium-ion secondary battery electrodes face challenges such as long predoping times, non-uniform lithium distribution, high internal resistance, and decreased cycle characteristics due to the reactivity of lithium metal powder and limitations in binding agents and solvents used.
Innovation Solution
A manufacturing method involving the use of alkaline metal or alkaline earth metal powders with coated surfaces, combined with electrode active materials and binding agents through dry mixing and compression forming, which eliminates the need for solvents and reduces predoping time, enhancing adhesion and cycle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium metal powder is used for predoping in a non-aqueous solvent, then lithium doping capacity increases, but adhesion of electrode decreases and cycle characteristic deteriorates due to residual lithium metal and high reactivity
Solution Approach 1:
The patent introduces a polymer-coated lithium metal powder as an intermediary material. The polymer coating acts as a mediator that prevents direct contact between lithium metal and the electrode material during mixing, eliminating the harmful effects of residual lithium metal while still enabling lithium doping capacity. This resolves the contradiction by using the polymer layer as a protective intermediary that maintains adhesion and cycle characteristics.
Solution Approach 2:
The patent changes the physical and chemical parameters of lithium metal by coating it with polymer. This transformation converts reactive lithium metal into polymer-coated lithium metal powder with controlled reactivity. The polymer coating modifies the surface properties, preventing direct reaction with electrode materials while maintaining lithium doping functionality, thus improving cycle characteristic while preserving doping capacity.
2Quantity of substance
If lithium metal powder is used for predoping, then lithium doping capacity increases, but predoping time increases due to high reactivity and deterioration of lithium metal
Solution Approach 1:
The polymer coating serves as a protective intermediary that stabilizes lithium metal powder during storage and processing. This prevents deterioration and extends the usable lifetime of lithium metal powder, enabling longer predoping times without loss of reactivity or capacity, thus resolving the time-related contradiction.
Solution Approach 2:
The patent performs preliminary coating of lithium metal with polymer before the predoping process. This preliminary action protects the lithium metal from oxidation and deterioration during storage and handling, maintaining its reactivity and doping capacity throughout the predoping process, thereby preventing time-related degradation.
3Ease of manufacture
If lithium metal powder is applied and dried to a current collector, then electrode formation is achieved, but lithium metal powder migrates and does not uniformly disperse, increasing internal resistance
Solution Approach 1:
The polymer coating acts as a dispersing intermediary that prevents aggregation and migration of lithium metal powder particles during the application and drying processes. The polymer layer provides steric stabilization, ensuring uniform distribution of lithium-containing particles throughout the electrode matrix, thereby achieving both ease of manufacture and manufacturing precision.
Solution Approach 2:
The patent changes the surface properties of lithium metal powder by coating with polymer, which modifies particle-particle and particle-substrate interactions. This parameter change prevents migration during drying and ensures uniform dispersion in the electrode, resolving the contradiction between ease of manufacture and uniformity.
4Ease of manufacture
If conventional wet mixing method is used with lithium metal powder, then electrode composition is achieved, but binding agent selection is limited due to high reactivity of lithium metal
Solution Approach 1:
The polymer-coated lithium metal powder introduces a new intermediary layer that is compatible with both aqueous and non-aqueous binding agents. This polymer coating acts as a universal interface that prevents direct reaction between lithium metal and various binding agents, thereby expanding binding agent selection while maintaining ease of manufacture.
Solution Approach 2:
The polymer coating provides universal compatibility with multiple types of binding agents (both aqueous and non-aqueous). This multi-functional approach allows the use of diverse binding agents without concern for lithium metal reactivity, enhancing adaptability and versatility in electrode formulation while maintaining ease of manufacture.
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
This method results in electrodes with improved adhesion, reduced internal resistance, and enhanced charge-discharge cycle characteristics, leading to higher productivity and energy density in electrochemical elements.
Implementation Method 1
a preparing step of a mixed powder by dry mixing the composite particles (A) and the alkaline metal powder or the alkaline earth metal powder, each having a coated surface
Implementation Method 2
a foaming step of an electrode composition layer by compression forming the mixed powder
Data Source
AI summary
Disclosed is a manufacturing method of an electrode for an electrochemical element having a superior adhesion and is used for an electrochemical element with excellent productivity due to a short predoping time. Specifically disclosed is that the method is characterized by comprising a step for compression forming of electrode material (a mixed powder or composite particles) including an alkaline metal powder or an alkaline earth metal powder each having a coated surface.