Solid State Battery Porous Electrode Infiltration

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Solution Overview

Problem

Current solid-state sodium batteries face challenges in operating efficiently at room temperature due to limited interfacial contact between electrolytes and electrodes, leading to structural instability and high capacity degradation, with existing methods resulting in low coulombic efficiency and limited cycle stability.

Innovation Solution

The method involves infiltrating nanoparticles of electrode active materials into a porous solid electrolyte framework, using a precursor solution that is heat-treated in a reducing atmosphere to synthesize active electrode materials homogeneously on the electrolyte's surface, enhancing ionic conductivity and structural stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If solid electrolyte and solid electrode materials are used in contact, then chemical stability and non-flammability are improved, but interfacial contact area is limited leading to high capacity degradation

Engineering Contradiction:
Improvechemical stabilityVSAvoidinterfacial contact area
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent employs a porous solid electrolyte with controlled pore size (0.1-10 μm) that allows infiltration of electrode materials into the pore structure. This creates extensive interfacial contact area while maintaining the solid-state chemical stability and non-flammability of the electrolyte material.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The electrode material is infiltrated into the porous structure of the solid electrolyte, creating a nested configuration where electrode particles are distributed within the electrolyte matrix. This maximizes interfacial contact area while maintaining the structural integrity of the solid-state battery.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Ease of manufacture

If electrode materials are mechanically mixed with electrolyte, then manufacturing simplicity is improved, but interfacial contact stability deteriorates during charging and discharging

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidinterfacial contact stability
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The porous electrolyte structure provides a fixed framework that prevents electrode material displacement during volume changes. The infiltration process creates stable mechanical interlocking between electrode and electrolyte, maintaining interfacial contact stability throughout charging and discharging cycles.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The electrode material is infiltrated into the porous electrolyte structure before final battery assembly. This preliminary infiltration ensures stable interfacial contact is established in advance, preventing contact loss during subsequent operational volume changes.

Inventive Principle:
Principle #10Preliminary action

3Quantity of substance

If solid-state battery design is implemented, then energy density is improved, but operating temperature requirements increase above 65°C

Engineering Contradiction:
Improveenergy densityVSAvoidoperating temperature
Core Design Contradiction:
Quantity of substanceVSTemperature

Solution Approach 1:

The porous electrolyte structure with optimized pore size enhances ion transport pathways, improving ionic conductivity at lower temperatures. This allows the solid-state battery to achieve high energy density while operating efficiently at room temperature rather than requiring elevated temperatures above 65°C.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The patent modifies the electrolyte structure by creating porosity, which changes the physical parameters of ion transport. This structural modification enables efficient ion conduction at lower temperatures, allowing the battery to operate at room temperature while maintaining high energy density.

Inventive Principle:
Principle #35Parameter changes

4Manufacturing precision

If infiltration method is used to introduce electrode particles, then interfacial contact area is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveinterfacial contact areaVSAvoidmanufacturing process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The porous electrolyte structure naturally provides the framework for electrode infiltration. The pore structure guides the infiltration process and ensures uniform distribution of electrode material, achieving high interfacial contact area while the porosity itself is created through straightforward ceramic processing techniques.

Inventive Principle:
Principle #31Porous 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 enables solid-state batteries to maintain high capacity and cycle stability, with coulombic efficiency exceeding 99% and minimal capacity degradation over 100 cycles, outperforming previous sodium and lithium-ion batteries in terms of performance.

Implementation Method 1

solid-state batteries use a solid electrolyte, such as ceramic, which makes them chemically and temperature-stable

Methodology Applied
Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 2

using a precursor solution that is heat-treated in a reducing atmosphere to synthesize active electrode materials

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Implementation Method 3

heat-treated in a reducing atmosphere to synthesize active electrode materials

Methodology Applied
Scientific EffectReduction: Reduction

Data Source

PatentEP3925023B1Solid state battery and method for producing same
Publication Date: 2023.05.10 FORSCHUNGSZENTRUM JULICH GMBH
  • EP3925023B1 patent drawingFigure 1
  • EP3925023B1 patent drawingFigure 2
  • EP3925023B1 patent drawingFigure 3~4

AI summary

The invention relates to a method for producing an electrode for a solid state battery, in which method a multi-layer ceramic solid electrolyte is provided, which comprises at least one dense layer and one porous layer and has a total ion conductivity of at least 1 mS / cm at 25 °C. An infiltration fluid is provided, in which at least one precursor of an electrode material is present in solution. Said infiltration fluid is introduced into the porous region of the solid electrolyte. The solid electrolyte is subjected to a thermal treatment in a reductive atmosphere at temperatures of between 400 °C and 900 °C, whereby the electrode material is synthesized in situ on the surface of the pores from the precursor of the electrode material. The solid state battery according to the invention comprises a multi-layer ceramic solid electrolyte, which comprises at least one dense layer and one porous layer and in the case of which the dense layer has a total ion conductivity of at least 1 mS / cm at 25 °C. The porous layer has continuous and open pores having an average diameter of less than 10 μm, on the surface of which pores the active electrode material produced in situ is arranged.