Cellulose Polymer Composite Solid Electrolyte for Battery Interface Resistance

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Solution Overview

Problem

Current all-solid-state secondary batteries face challenges with increased interface resistance due to hard solid electrolytes, which affect ion conductivity and binding properties, and existing polymer binders do not meet high standards required for improved performance.

Innovation Solution

Incorporating a cellulose polymer with specific repeating units and a high degree of substitution into the inorganic solid electrolyte layers to enhance ion conductivity and binding properties, while using an inorganic solid electrolyte with conductivity of metals from Group 1 or 2 of the periodic table.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an inorganic solid electrolyte is used, then reliability and incombustibility are improved, but interface resistance increases

Engineering Contradiction:

ImprovereliabilityVSAvoidinterface resistance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A polymer binder serves as an intermediary substance between the inorganic solid electrolyte particles and electrode materials. This polymer mediator fills the gaps between hard solid particles, providing a flexible bonding matrix that reduces interface resistance while maintaining the structural integrity and reliability benefits of the inorganic solid electrolyte.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention creates a composite structure combining inorganic solid electrolyte particles with a polymer binder matrix. This composite material approach allows the system to simultaneously exhibit the high reliability and incombustibility of inorganic materials while the polymer component provides flexibility and reduced interface resistance, resolving the contradiction between these properties.

Inventive Principle:

Principle #40Composite materials

2Strength

If a polymer binder is used to reduce interface resistance, then binding properties improve, but ion conductivity may be compromised

Engineering Contradiction:

Improvebinding propertiesVSAvoidion conductivity

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The invention optimizes parameters including the type of polymer binder used, its concentration within the composite, molecular weight, and degree of crosslinking. By carefully controlling these parameters, the polymer binder provides sufficient binding strength while maintaining adequate ion conductivity pathways through the composite material.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The polymer binder is strategically positioned in specific locations within the composite structure, primarily at the interfaces between inorganic solid electrolyte particles and electrode materials. This localized placement ensures binding properties are enhanced where needed most, while minimizing the polymer's impact on overall ion conductivity by keeping it away from primary ion transport pathways.

Inventive Principle:

Principle #3Local quality

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 solution achieves high ion conductivity and satisfactory binding properties, leading to improved performance and manufacturing of all-solid-state secondary batteries with enhanced characteristics.

Implementation Method 1

at least one of the positive electrode active substance layer, the negative electrode active substance layer, or the inorganic solid electrolyte layer contains an inorganic solid electrolyte having conductivity of ions of metal belonging to Group 1 or 2 of the periodic table

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 2

the binders consisting of polymer compounds disclosed in the documents above may not meet the high standards currently required and new improvements therein are required

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS10297859B2All-solid-state secondary battery, solid electrolyte composition and electrode sheet for batteries used in the same, and manufacturing method of electrode sheet for batteries and all-solid-state secondary battery

Publication Date: 2019.05.21 FUJIFILM CORP

AI summary

An all-solid-state secondary battery includes a positive electrode active substance layer; a negative electrode active substance layer; and an inorganic solid electrolyte layer, in which at least one of the positive electrode active substance layer, the negative electrode active substance layer, or the inorganic solid electrolyte layer contains an inorganic solid electrolyte having conductivity of ions of metal belonging to Group 1 or 2 of the periodic table and a cellulose polymer.