Air Electrode-Separator Assembly With Water Buffering for Metal-Air Cells
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Solution Overview
Problem
Metal-air secondary batteries with layered double hydroxide (LDH) separators face challenges in charge/discharge performance due to the blocking of electrolyte permeation into the air electrode, leading to reduced water circulation and decreased performance compared to batteries with general porous polymer separators.
Innovation Solution
An air electrode/separator assembly is designed with a hydroxide ion conductive separator, catalyst layers, gas diffusion electrodes, and a water absorption/desorption layer to facilitate water circulation and maintain charge/discharge performance, incorporating a water absorbent resin and silica gel in the water absorption/desorption layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an LDH separator is used to block zinc dendrite penetration and prevent short circuits, then battery safety and dendrite resistance are improved, but electrolyte permeation into the air electrode is blocked, leading to reduced water circulation and decreased charge/discharge performance
Solution Approach 1:
The separator is divided into two functional layers: an LDH layer for blocking zinc dendrites and a porous polymer layer for enabling electrolyte permeation and water circulation. This segmentation allows each layer to specialize in one function, resolving the contradiction between dendrite resistance and charge/discharge performance
Solution Approach 2:
The separator combines LDH (layered double hydroxide) with a porous polymer material to create a composite structure. The LDH provides dendrite blocking capability while the porous polymer enables electrolyte permeation, achieving both high reliability and productivity simultaneously
2Productivity
If a general porous polymer separator is used to allow electrolyte permeation and water circulation, then charge/discharge performance is improved, but the separator cannot effectively block zinc dendrite penetration and prevent short circuits
Solution Approach 1:
The separator is divided into two functional layers: an LDH layer for blocking zinc dendrites and a porous polymer layer for enabling electrolyte permeation and water circulation. This segmentation allows each layer to specialize in one function, resolving the contradiction between dendrite resistance and charge/discharge performance
Solution Approach 2:
The separator combines LDH (layered double hydroxide) with a porous polymer material to create a composite structure. The LDH provides dendrite blocking capability while the porous polymer enables electrolyte permeation, achieving both high reliability and productivity simultaneously
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 assembly enhances charge/discharge performance by allowing water absorption and desorption, maintaining moisture levels in the air electrode, thereby improving the battery's reaction efficiency and longevity.
Implementation Method 1
a water absorption/desorption layer provided so as to contact both of the pair of catalyst layers, having water absorbability and desorbability
Implementation Method 2
a water absorption/desorption layer provided so as to contact both of the pair of catalyst layers, having water absorbability and desorbability
Implementation Method 3
a hydroxide ion conductive separator comprising an inner space capable of housing a metal negative electrode
Data Source
AI summary
Provided is an air electrode/separator assembly including a hydroxide ion conductive separator including an inner space, a pair of catalyst layers covering both surfaces of the hydroxide ion conductive separator and containing a catalyst for an air electrode, a hydroxide ion conductive material, and an electron conductive material, a pair of gas diffusion electrodes provided on the pair of catalyst layers on a side opposite to the hydroxide ion conductive separator, and a water absorption/desorption layer provided so as to contact both of the pair of catalyst layers, having water absorbability and desorbability. One of the pair of catalyst layers is a catalyst layer for discharge and the other of the pair of catalyst layers is a catalyst layer for charge; and the hydroxide ion conductive separator, the catalyst layer, and the gas diffusion electrode are arranged vertically, and the water absorption/desorption layer is positioned below the catalyst layer.