Alkaline Metal Battery Anode Carbon Layer Pores

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Solution Overview

Problem

Lithium-based solid-state batteries face challenges with mechanical stresses and limited specific capacity due to a 2-dimensional interface, restricting their application and scalability, especially when using graphite anodes.

Innovation Solution

An alkali metal secondary battery design featuring a carbon layer with specific pores that are not accessible to the electrolyte, allowing efficient uptake of metallic alkali metal during charging, and a three-dimensional interface for enhanced charge transport and reduced mechanical stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a 2-dimensional interface is used for lithium ion transport, then the battery structure is simple, but the specific capacity is limited and mechanical stresses occur

Engineering Contradiction:

Improveinterface structureVSAvoidspecific capacity

Core Design Contradiction:

Device complexityVSQuantity of substance

Solution Approach 1:

The patent transitions from a 2-dimensional interface to a 3-dimensional pore network structure. The carbon layer contains interconnected pores that extend throughout the material volume, allowing lithium ions to access multiple pathways and significantly increasing the effective interface area for ion transport and metal deposition.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The invention employs a porous carbon layer as the anode material. The porous structure provides high surface area-to-volume ratio, enabling increased lithium ion accommodation capacity while maintaining structural integrity and reducing mechanical stresses during charge-discharge cycles.

Inventive Principle:

Principle #31Porous materials

2Reliability

If graphite anodes are used, then the battery operates stably, but the specific capacity is limited to 372 mAh/g

Engineering Contradiction:

Improveoperational stabilityVSAvoidspecific capacity

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent uses porous carbon materials that combine the stability advantages of graphite with enhanced capacity. The carbon layer can be composed of various carbon forms (amorphous carbon, carbon black, graphene, graphite-like carbon, carbon fibers, carbon nanofibers, carbon hollow spheres) that provide both structural stability and increased lithium ion accommodation capacity beyond conventional graphite limits.

Inventive Principle:

Principle #40Composite materials

3Quantity of substance

If metallic lithium anodes are used, then the specific capacity increases, but mechanical stresses and dendrite formation occur

Engineering Contradiction:

Improvespecific capacityVSAvoidmechanical stress

Core Design Contradiction:

Quantity of substanceVSStress or pressure

Solution Approach 1:

The porous carbon layer provides a three-dimensional network that accommodates metallic lithium deposition throughout the pore volume rather than at a single interface. This distributes the mechanical stress across the entire carbon structure, preventing the formation of dendrites and reducing stress on the solid electrolyte while maintaining high specific capacity.

Inventive Principle:

Principle #31Porous materials

4Power

If high charging currents are applied, then the power density increases, but mechanical stresses and dendrite formation are exacerbated

Engineering Contradiction:

Improvepower densityVSAvoidcycle stability

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The 3-dimensional pore network provides multiple parallel pathways for lithium ion transport, distributing the current density across a larger effective area. This allows high charging currents to be applied without concentrating stress at a single interface, enabling high power density while maintaining cycle stability and preventing dendrite formation.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 battery achieves high specific capacity, power density, and cycle stability with reduced mechanical stress, leading to increased long-term stability and operational reliability.

Implementation Method 1

the carbon layer comprises pores of a first type which are not accessible to the electrolyte and which are suitable for taking up electrochemically deposited alkali metal in metallic form during a charging process

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 2

an electrolyte arranged between the cathode and anode and having an alkali metal ion-conductive contact to the cathode and to the carbon layer of the anode

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Data Source

PatentUS20220359872A1Alkaline metal secondary battery and uses thereof

Publication Date: 2022.11.10 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV

AI summary

The invention relates to alkaline secondary batteries. The secondary battery contains a cathode, an anode and an electrolyte, said secondary battery being arranged between the cathode and anode and comprises an alkali metal ion conductive contact to the cathode and to the carbon layer of the anode. The anode contains or consists of a carbon layer, whereby the carbon layer, alone or in combination with an electrically conductive substrate, forms with an electrically conductive contact.