Solid-State Battery Cell Templates for Stable 3D Electrode Coating

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Solution Overview

Problem

Current methods for fabricating solid-state batteries with three-dimensional electrode structures face challenges in conformal coating of active electrode materials and maintaining mechanical stability, due to issues with barrier layer removal in porous anodic aluminum oxide templates and the instability of acidic electroplating baths.

Innovation Solution

A method involving anodization of valve metals to form templates with spaced channels, followed by protective treatment and controlled etching to remove barrier layers, allowing for conformal deposition of active electrode materials without pore widening or narrowing, and using neutral electroplating baths for large-scale manufacturing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the barrier layer is removed by immersing the template in H3PO4 solution, then the barrier layer is removed from channel bottoms, but excessive pore widening occurs resulting in large diameter nanowires that limit energy density

Engineering Contradiction:
Improvebarrier layer removalVSAvoidpore volume available for active material
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

A thin metal layer is deposited on the channel bottoms before removing the barrier layer. This preliminary action provides mechanical support to prevent excessive pore widening during subsequent H3PO4 etching, while still allowing complete barrier layer removal for reliable nanowire formation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The metal layer acts as an intermediary between the barrier layer removal process and the final pore structure. It mediates the etching process by providing structural support that prevents uncontrolled pore widening, enabling complete barrier layer removal without sacrificing pore volume for active material.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If the voltage is gradually reduced during the final stage of anodization, then the barrier layer thickness is reduced to allow electroplating, but long thin root-like nanowires are formed resulting in poor mechanical stability

Engineering Contradiction:
Improvebarrier layer thicknessVSAvoidmechanical stability of nanowire network
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

A metal layer is deposited as an intermediary structure at the channel bottoms before nanowire formation. This metal layer acts as a robust foundation that replaces the mechanically weak root-like nanowires, providing strong mechanical support while allowing the barrier layer to be sufficiently thin for electroplating.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The metal layer is deposited in advance before the barrier layer removal and nanowire formation steps. This preliminary action establishes a strong mechanical foundation that prevents the formation of weak root-like structures, ensuring both manufacturability and mechanical stability.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If electroplating is performed in acidic baths, then metal nanowires can be formed, but the electroplating process is unstable and difficult to implement in large-scale manufacturing

Engineering Contradiction:
Improvenanowire formationVSAvoidelectroplating process stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The pH parameter of the electroplating bath is changed from acidic to neutral. This parameter change stabilizes the electroplating process, eliminating the instability and reliability issues associated with acidic baths while still enabling effective metal nanowire formation on the prepared channel bottoms.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If the template is separated from the underlying aluminum foil, then the barrier layer can be removed from channel bottoms, but the template becomes fragile and hard to implement in large-scale manufacturing

Engineering Contradiction:
Improvebarrier layer removalVSAvoidmanufacturing scalability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

A metal layer is deposited on the channel bottoms before barrier layer removal. This preliminary reinforcement allows the barrier layer to be completely removed without requiring template separation, maintaining template integrity and enabling large-scale manufacturing while achieving reliable barrier layer removal.

Inventive Principle:
Principle #10Preliminary action

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 method enables the formation of solid-state battery cells with improved mechanical stability and energy density by maintaining the structural integrity of the electrode structures and ensuring the stability of the electroplating process, suitable for large-scale production.

Implementation Method 1

a plurality of spaced structures are formed by transforming aluminium into anodic aluminium oxide comprising channels by a single anodization step

Methodology Applied
Scientific EffectAnodization: Anodising

Implementation Method 2

a first layer of active electrode material is coated on the plurality of spaced structures; an electrolyte layer is deposited over the first layer of active electrode material; a second layer of active electrode material is formed over the electrolyte layer

Methodology Applied
Scientific EffectElectroplating: Electroplating

Data Source

PatentEP3655571B1Fabrication of solid-state battery cells
Publication Date: 2023.10.25 INTERUNIVERSITAIR MICRO ELECTRONICS CENT (IMEC VZW)
  • EP3655571B1 patent drawingFigure 1
  • EP3655571B1 patent drawingFigure 2~3
  • EP3655571B1 patent drawingFigure 4~5

AI summary

Methods for fabricating solid-state battery cells and batteries are provided, as well as solid-state battery cells and batteries thus fabricated.These methods may relate to the transformation of at least part of a valve metal layer into a template comprising a plurality of spaced (nano)channels, and/or to the formation of a plurality of spaced structures inside the (nano)channels of the template. They may further relate to the formation of a layer of functional material on an electrically conductive substrate.