Zinc-Air Electrode Design for Moisture Management

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Solution Overview

Problem

Zinc-air batteries face challenges in achieving high power output and rate capability due to issues with moisture flooding at the air electrode and unwanted interactions between active and inactive components, which are not adequately addressed by single-component or single-additive solutions that often neglect the effects on other aspects of the cell design.

Innovation Solution

The use of a catalytic air electrode with specific types of conductive carbons, laminated barrier layers, and additives that form a thin, robust film on the zinc surface, along with a balanced mixture of carbons from different sources in the air electrode, to optimize hydrophobic and hydrophilic properties and enhance oxygen diffusion and reaction rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hydrophobic properties are increased on the external face of the air electrode to prevent moisture flooding, then moisture resistance is improved, but oxygen diffusion and electrochemical reaction rates are impeded

Engineering Contradiction:

Improvemoisture resistanceVSAvoidoxygen diffusion rate

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The air electrode is designed with different surface properties at different locations: the external face has hydrophobic properties to repel moisture, while the internal face has hydrophilic properties to facilitate oxygen diffusion and electrochemical reactions. This spatial differentiation of properties allows simultaneous achievement of moisture resistance and high reaction rate.

Inventive Principle:

Principle #3Local quality

2Reliability

If inactive additives and components are used to mitigate gassing and passivation effects, then reliability is improved, but energy density decreases due to volume occupation

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidenergy density

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The zinc electrode uses a controlled amount of inactive additives (0.1-5 wt%) to mitigate gassing and passivation. This optimized parameter range provides sufficient corrosion protection while minimizing volume occupation, thereby maintaining high energy density.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If single-component or single-additive solutions are used to improve zinc-air cell performance, then device complexity is reduced, but overall performance is insufficient due to neglected interactions with other cell aspects

Engineering Contradiction:

Improvedesign simplicityVSAvoidpower output

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The air electrode uses a composite structure combining hydrophobic external face material and hydrophilic internal face material. The zinc electrode uses a composite formulation of active zinc material with controlled amounts of inactive additives. These composite approaches enable synergistic performance improvements without excessive complexity.

Inventive Principle:

Principle #40Composite materials

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 approach improves the overall performance and reliability of zinc-air batteries by preventing moisture flooding, reducing corrosion, and maintaining high rate capability, while minimizing the volume occupied by inactive components, thereby enhancing energy density and power output.

Implementation Method 1

The air diffuses into the cell through an air electrode structure that catalytically promotes the reduction of oxygen in the presence of an aqueous electrolyte

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 2

catalytically promotes the reduction of oxygen

Methodology Applied

Scientific EffectOxygen reduction reaction: Redox Reactions

Implementation Method 3

a failure to properly engineer the external face (i.e., the side of the electrode exposed to the ambient atmosphere) with sufficient hydrophobic properties could lead to unwanted moisture 'flooding' the electrode surface

Methodology Applied

Scientific EffectHydrophobic effect: Hydrophobe

Implementation Method 4

The use of a catalytic air electrode with specific types of conductive carbons

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 5

additives that form a thin, robust film on the zinc surface, along with a balanced mixture of carbons from different sources in the air electrode, to optimize hydrophobic and hydrophilic properties and enhance oxygen diffusion and reaction rates

Methodology Applied

Scientific EffectFilm formation: Coatings

Data Source

PatentUS20190051958A9Zinc-air electrochemical cell

Publication Date: 2019.02.14 ENERGIZER BRANDS LLC

AI summary

A multi-faceted zinc-air electrochemical cell design holistically leverages interactions between components, especially with respect to conductive carbons from differing sources, lamination and the resulting impact it has on the air electrode's surface and other additives that impact the relative hydrophilicity of the membrane and/or performance of the anode, to improve the overall reliability and performance of the resulting battery.