Silicon-Air Button Cell With Porous Anode for Lithium-Free Power

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Solution Overview

Problem

There is a growing need for environmentally friendly and cost-effective battery technologies that can provide high power density and are lithium-free, particularly for applications like hearing aids, where batteries must be recyclable and have unlimited raw material availability.

Innovation Solution

The development of an electrochemical silicon-air primary cell using silicon as the anode material, with a porous framework and doped silicon particles, and an air cathode utilizing atmospheric oxygen, which achieves high power densities and efficiency with KOH or carbonate-containing electrolytes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional lithium-containing batteries are used, then high energy density is achieved, but environmental friendliness and recyclability are compromised

Engineering Contradiction:
Improveenergy densityVSAvoidenvironmental friendliness
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters by replacing lithium-containing materials with silicon-based materials. The anode is changed from lithium metal or lithium compounds to silicon particles (amorphous or crystalline), and the electrolyte is changed from lithium salt solutions to alkaline solutions (KOH, NaOH) or carbonate solutions, thereby eliminating lithium while maintaining battery functionality and improving environmental compatibility

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs disposable silicon particles as the anode material, which are inexpensive, abundant, and can be easily replaced. The silicon particles are used in a primary (non-rechargeable) cell configuration, allowing the battery to be discarded after use rather than requiring complex recycling infrastructure, thus simplifying the environmental sustainability approach

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Object-affected harmful factors

If lithium-free silicon anodes are used, then environmental friendliness is improved, but power density and starting voltage are reduced

Engineering Contradiction:
Improveenvironmental friendlinessVSAvoidpower density
Core Design Contradiction:
Object-affected harmful factorsVSPower

Solution Approach 1:

The patent applies local quality by creating a porous structure of silicon particles with specific surface area characteristics. The silicon particles are designed with controlled porosity (specific surface area of 0.1-10 m²/g) to optimize the local reaction sites, ensuring high power density is achieved at the particle surfaces while maintaining the overall lithium-free composition. The porous framework provides numerous active sites for electrochemical reactions

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining silicon particles with porous frameworks (such as carbon-based materials or metal oxides). This composite structure enhances the electrical conductivity and structural stability of the anode, compensating for the lower intrinsic power density of lithium-free materials. The composite approach allows silicon to function effectively without lithium while maintaining high power output

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If silicon particles with large size are used, then manufacturing simplicity is improved, but reaction efficiency and power density are reduced

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidreaction efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent segments the silicon anode into numerous small particles (amorphous or crystalline silicon particles) with controlled size distribution. This segmentation increases the total surface area available for electrochemical reactions, dramatically improving reaction efficiency and power density. The segmented particle structure allows the battery to achieve high performance despite the complexity of manufacturing fine particles

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs porous materials by creating a porous framework from silicon particles with specific surface area of 0.1-10 m²/g. This porous structure provides high surface area to volume ratio, enabling efficient electrolyte penetration and ion transport throughout the anode structure. The porosity enhances reaction efficiency by exposing more active sites while maintaining structural integrity and facilitating manufacturing through conventional powder processing techniques

Inventive Principle:
Principle #31Porous materials

4Power

If high power density is achieved, then energy delivery rate is improved, but cell voltage stability is reduced

Engineering Contradiction:
Improvepower densityVSAvoidvoltage stability
Core Design Contradiction:
PowerVSStability of the object's composition

Solution Approach 1:

The patent introduces porous frameworks (carbon materials, metal oxides, or other intermediary substances) that act as mediators between the silicon particles and the electrolyte. These intermediary materials provide stable conductive pathways and buffer the voltage fluctuations that occur during high-rate discharge. The porous framework maintains structural stability while facilitating efficient electron and ion transport, thus stabilizing cell voltage during high power density operation

Inventive Principle:
Principle #24Intermediary (Mediator)

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 silicon-air primary cell achieves power densities of up to 100 microwatts/mm² and an efficiency of over 87%, with the ability to deliver energy for 140-160 minutes, while being lithium-free and utilizing recyclable materials.

Implementation Method 1

After the atmospheric oxygen has undergone the chemical reaction at the cathode to form a hydroxide ion (OH−), the silicon anode, consisting of the silicon particle mixture (granules, silicon syrup, silicon plate, or silicon foil), undergoes the oxygen reduction reaction to produce stable cell voltages (discharge voltage)

Methodology Applied
Scientific EffectOxygen reduction reaction: Redox Reactions

Implementation Method 2

the silicon anode, consisting of the silicon particle mixture (granules, silicon syrup, silicon plate, or silicon foil), undergoes the oxygen reduction reaction to produce stable cell voltages (discharge voltage)

Methodology Applied
Scientific EffectElectrochemical reaction: Redox Reactions

Implementation Method 3

In the anode material, silicon can be present as an anode in the form of a shaped body, particularly a porous one, preferably with a porous framework, formed from silicon particles

Methodology Applied
Scientific EffectPorosity: Porosity

Data Source

PatentEP4235837A1Electrochemical silicon air button cell
Publication Date: 2023.08.30 XENIONIK GMBH & CO KG
  • EP4235837A1 patent drawingFigure 1~2
  • EP4235837A1 patent drawingFigure 3a~3c
  • EP4235837A1 patent drawingFigure 4~5a.3

AI summary

The invention relates to an electrochemical silicon-air primary cell as a silicon-air button cell 0 as well as a kit with a protective film and in a sales or storage package 11 as well as the use of silicon in a silicon-air primary cell as a button battery.