Electroplated Zinc Negative Electrodes for Metal Cells
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Solution Overview
Problem
Existing zinc electrodes in electrochemical cells face issues with low conductivity, high polarization, non-uniformity, and reduced capacity due to inadequate zinc utilization, leading to decreased specific energy and energy density, especially in secondary cells where dendrite growth and internal short-circuits can occur.
Innovation Solution
A method of fabricating a zinc electroplated electrode using an electroplating process with a zinc electroplating system comprising a zinc anode, a conductive current collector, and an electrolyte bath containing Zn2+ or [Zn(OH)4]2− ions, which bonds zinc metal to the current collector, enhancing conductivity and uniformity, and allowing for the use of various zinc forms and electrolyte types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If zinc powder is used as a slurry/paste applied to a conductive current collector, then the zinc electrode can be formed, but the zinc powder is highly susceptible to oxidation in air or certain electrolytes, forming an electrically insulating oxide layer that prevents metallic zinc from being accessed
Solution Approach 1:
The patent uses a composite structure where zinc metal is electroplated onto a conductive current collector substrate. This composite design combines the high zinc content needed for capacity with the conductive substrate that prevents oxidation and maintains electrical connectivity, resolving the contradiction between manufactability and oxidation resistance.
Solution Approach 2:
The electroplating process performs a preliminary protective action by depositing zinc metal directly onto the current collector in a controlled environment before the electrode is exposed to air or electrolytes. This preliminary metallurgical bonding prevents subsequent oxidation issues that plague zinc powder slurries.
2Reliability
If a sufficient conductivity is not maintained in the zinc electrode, then some zinc metal will be inactive and remain at the negative electrode, but maintaining high conductivity requires additional measures that increase device complexity
Solution Approach 1:
The electroplated zinc metal layer serves itself by maintaining inherent electrical conductivity through direct metallurgical bonding to the conductive current collector. The structure is self-sufficient, requiring no additional conductive additives or complex conductive network designs, thus achieving high zinc utilization without increasing device complexity.
3Ease of manufacture
If zinc powder is used in the electrode, then the electrode can be manufactured, but the oxide layer formed on zinc particles prevents metallic zinc from being accessed, leading to reduced capacity
Solution Approach 1:
The patent replaces the mechanical mixing and binding process used in zinc powder slurries with an electrochemical electroplating process. This substitution creates a metallurgically bonded zinc layer that is inherently conductive and accessible, eliminating the oxidation problem that reduces active zinc capacity in powder-based electrodes.
4Reliability
If non-uniform stripping/plating occurs in low conductivity zinc electrodes, then dendrites and internal short-circuits may grow, but improving conductivity requires electroplating which increases process complexity
Solution Approach 1:
The conductive current collector acts as an intermediary substrate that enables uniform zinc deposition during electroplating. It serves as a stable platform that distributes current evenly, preventing dendrite formation and ensuring uniform stripping/plating cycles, while the electroplating process itself is a成熟 industrial technology that manages complexity 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 electroplated zinc electrodes demonstrate improved conductivity, reduced polarization, and increased capacity, maintaining morphology during cycling and extending cycle life, with the ability to be used in both primary and secondary zinc metal cells.
Implementation Method 1
fabricating an electroplated zinc electrode including a layer of zinc metal bonded to a surface of a current collector using an electroplating process
Implementation Method 2
an electroplating process bonds the zinc metal to the current collector
Data Source
AI summary
A method of fabricating and using a zinc negative electrode and systems thereof are described. A zinc electroplated electrode including a layer of zinc metal bonded to a surface of an electrically conductive current collector is fabricated by an electroplating process using a zinc electroplating system. The zinc electroplating system includes: a zinc metal anode, a cathode including the current collector for plating zinc thereon, and an electrolyte bath comprising zinc ions. The electroplating process bonds the zinc metal to the surface of the current collector to create the electroplated zinc electrode. The electroplated zinc electrode is used as a negative electrode in a zinc metal cell. The zinc metal cell may be a primary cell or a secondary cell.