Solid Electrode Plasticizer Layer for Interfacial Resistance

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Solution Overview

Problem

Solid electrolyte batteries face issues with interfacial resistance and adhesion between the positive electrode active material layer and the separator, leading to rapid degradation due to voids and cracking, which are exacerbated by the absence of liquid electrolyte infiltration.

Innovation Solution

A positive electrode design for solid electrolyte batteries that includes a first active material layer without plasticizer for mechanical integrity and a second active material layer with a plasticizer that softens at elevated temperatures to reduce interfacial resistance and allow electrolyte infiltration into cracks, maintaining adhesion to the current collector.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a liquid electrolyte is injected into the battery after assembly to fill the interface between electrode and separator, then the interfacial resistance is reduced, but an excessive amount of liquid material must be injected and a separate liquid injection step is required

Engineering Contradiction:

Improveinterfacial resistanceVSAvoidliquid injection step

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The plasticizer is pre-incorporated into the solid electrolyte material during manufacturing, so that the electrolyte-filling function is already prepared in advance. During battery operation, the plasticizer naturally migrates to fill interfaces and cracks without requiring any additional injection steps or processes.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The plasticizer serves multiple functions simultaneously: it acts as a binder in the electrode structure, a plasticizer to maintain solid electrolyte flexibility, and a mobile electrolyte component that fills interfaces and cracks. This consolidation of multiple functions into a single material eliminates the need for separate liquid electrolyte injection steps.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If a liquid material is absorbed preliminarily into a polymer-based separator to soften it and reduce interfacial resistance, then the adhesion between separator and electrode is improved, but the softened separator has poor mechanical properties making assemblage difficult

Engineering Contradiction:

Improveinterfacial resistanceVSAvoidmechanical properties

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The plasticizer is distributed throughout the solid electrolyte and electrode materials, providing localized softening and flexibility where needed at interfaces and cracks, while the bulk solid electrolyte and separator maintain their structural integrity and mechanical strength for proper assemblage.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The solid electrolyte system combines a polymer matrix with plasticizer additives to create a composite material that exhibits both mechanical strength from the polymer structure and flexibility/electrolyte mobility from the plasticizer components, achieving a balance between structural integrity and interfacial compatibility.

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 design enhances ion conductivity and prevents battery degradation by maintaining mechanical properties and adhesion while reducing interfacial resistance and allowing electrolyte infiltration into cracks, similar to liquid electrolyte batteries.

Implementation Method 1

a second positive electrode active material layer formed on the first positive electrode active material layer and including a second positive electrode active material, a second solid electrolyte and a plasticizer

Methodology Applied

Scientific EffectPhase change (solid to liquid): Phase Change

Implementation Method 2

the plasticizer has a melting point of 30-130° C., wherein the solid electrolyte battery is activated at a temperature between the melting point of the plasticizer and 130° C., and the plasticizer is present in a liquid state after the solid electrolyte battery is activated

Methodology Applied

Scientific EffectInfiltration: Permeation

Data Source

PatentUS11444272B2Positive electrode including room temperature solid state plasticizer, and solid electrolyte battery including the same

Publication Date: 2022.09.13 LG ENERGY SOLUTION LTD

AI summary

The present disclosure relates to a positive electrode for a solid electrolyte battery which includes: a positive electrode current collector; a first positive electrode active material layer formed on at least one surface of the positive electrode current collector and including a first positive electrode active material, a first solid electrolyte and a first electrolyte salt; and a second positive electrode active material layer formed on the first positive electrode active material layer and including a second positive electrode active material, a second solid electrolyte, a second electrolyte salt and a plasticizer, wherein the plasticizer has a melting point of 30-130° C. The present disclosure also relates to a solid electrolyte battery including the positive electrode.