Water-Soluble Binder for TMHCM Electrodes

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Solution Overview

Problem

Transition metal hexacyanometallate electrodes in aqueous electrolytes face challenges such as low capacities and energy densities due to limited ion insertion, and the need for operation within a narrow electrochemical window, while conventional binders like PVDF require harmful organic solvents, increasing fabrication costs and environmental concerns.

Innovation Solution

A water-soluble binder, such as poly(acrylonitrile-co-acrylamide) polymer or carboxymethylcellulose, is used to fabricate transition metal hexacyanometallate electrodes, allowing for cost-effective and environmentally friendly production by dissolving in water and maintaining electrochemical stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional PVDF binder is used, then electrochemical stability is maintained, but harmful organic solvents are required and fabrication costs increase

Engineering Contradiction:

Improveelectrochemical stabilityVSAvoidharmful organic solvents

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the solvent parameter from organic (NMP) to water, eliminating harmful organic solvents while maintaining binder functionality through the use of water-soluble polymers like carboxymethylcellulose and polyvinyl alcohol

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention replaces expensive PVDF binder with cheaper water-soluble binder alternatives, reducing material costs while achieving comparable or improved electrode performance through cost-effective water-based fabrication processes

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Ease of manufacture

If water-soluble binder is used, then fabrication costs are reduced and environmental impact is minimized, but binder stability in aqueous electrolyte must be maintained

Engineering Contradiction:

Improvefabrication costVSAvoidbinder stability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The water-soluble binder serves dual functions: it acts as a binding agent during water-based fabrication and provides structural stability in the final aqueous electrolyte environment, eliminating the need for separate organic solvent processing steps

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The invention uses composite binder systems combining water-soluble polymers (carboxymethylcellulose, polyvinyl alcohol) with conductive additives to achieve both ease of water-based fabrication and long-term electrochemical stability in aqueous environments

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If transition metal hexacyanometallate electrodes are operated in aqueous electrolytes, then cost-effective fabrication is enabled, but capacities and energy densities are limited

Engineering Contradiction:

Improvefabrication costVSAvoidion insertion capacity

Core Design Contradiction:

Ease of manufactureVSQuantity of substance

Solution Approach 1:

The invention optimizes local electrode properties by using water-soluble binders that enhance ion transport pathways and electrode morphology, improving local ion insertion efficiency without requiring changes to the bulk aqueous electrolyte composition

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The water-soluble binder serves multiple functions simultaneously: it provides mechanical binding, enhances electrochemical stability, facilitates ion transport, and enables cost-effective water-based fabrication, making the system universally applicable to various transition metal hexacyanometallate compositions

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 use of water-soluble binders enables the production of high-quality electrodes with improved rate capability and mechanical properties, reducing fabrication costs and environmental impact while maintaining performance in sodium-ion batteries and other rechargeable metal-ion batteries.

Implementation Method 1

Methodology Applied

Scientific EffectDissolution: Solvation

Implementation Method 2

Transition metal hexacyanometallate electrodes in aqueous electrolytes face challenges such as low capacities and energy densities due to limited ion insertion

Methodology Applied

Scientific EffectIon insertion: Absorption (physical)

Data Source

PatentUS9666866B2Transition metal hexacyanometallate electrode with water-soluble binder

Publication Date: 2017.05.30 SHARP KK

AI summary

A method is provided for fabricating a transition metal hexacyanometallate (TMHCM) electrode with a water-soluble binder. The method initially forms an electrode mix slurry comprising TMHCF and a water-soluble binder. The electrode mix slurry is applied to a current collector, and then dehydrated to form an electrode. The electrode mix slurry may additionally comprise a carbon additive such as carbon black, carbon fiber, carbon nanotubes, graphite, or graphene. The electrode is typically formed with TMHCM greater than 50%, by weight, as compared to a combined weight of the TMHCM, carbon additive, and binder. Also provided are a TMHCM electrode made with a water-soluble binder and a battery having a TMHCM cathode that is made with a water-soluble binder.