ENGINEEREDFIBERS

TECHNOLOGY

Porous Graphite Materials Development for Specific

Electrochemical Applications

Presented By:

Robert E. EvansHannover MesseApril 13-17, 2015

Engineered Fibers TechnologyEstablished 1998

Engineered Fibers TechnologyEstablished 1998

Technical Expertise- Founding Members Each

With Over 30 Years Experience - Fibers / Composites / Paper

Providing High Technology Fibers /Materials / Services

Located in Shelton, CT(1950 Sq. Meters)

- Fiber Processing- Materials Development Lab- Spectracarb Development

Technical Expertise- Founding Members Each

With Over 30 Years Experience - Fibers / Composites / Paper

Providing High Technology Fibers /Materials / Services

Located in Shelton, CT(1950 Sq. Meters)

- Fiber Processing- Materials Development Lab- Spectracarb Development

Spectracarb GDL Background

From 1991-2005, Spectracorp. Ltd was

Leading producer of GDL products for commercial application- SpectracarbTM GDL

Leader in development of new GDL materialsDOE ContractsAutomotive / Industrial Sponsorship

Spectracarb GDL Background

Since 2005 EFT has grown Spectracarb Porous Graphite Materials through: Engineered Materials Research Wet-Laid Paper Development Specialty Short-Cut Fiber Investigations

Partnership with Caplinq Europe BV Since 2013

Technology Focus is Customer Driven / Customer Responsive GDL Development

Wet-Laid Resin Bonded Paper / Panels

Nonwoven Needle Punched Felts / Woven Fabrics

Production of Porous GDL Materials

Wet-Laid GDL Paper General Processing Schemes

PAN Filament

Carbon Filament

Carbon Fiber Slurry

Bonded Graphite Fiber Paper / Panel

Other Components

Resin Impregnation

Specific Porous Graphite Paper /

Panel

Wide Range of Carbon Fibers Available from producers Stabilization /

Graphitization900- 3000oC

Stabilization, carbonization

Precision Cutting

Molding /Resin CuringPaper Formation

Optional Wet-proofing, MPL

coating, sintering

Advantages of Papermaking Approach for Specialized GDL Products

Versatility - Wide Range of Fibers / Particle Modifiers/Binders Can be Included in Papermaking

Thickness / Density /Porosity Control

High Density /Thick Panels with High Compressive Compliance / Low Flow Channel Intrusion

Preparation on Laboratory / Pilot / Production Scale

Small Production Runs Possible

EFT / Spectracarb GDL Macroporous Graphite Materials EFT / Spectracarb GDL Macroporous Graphite Materials

Very High Conductivity Porous Graphite Papers / Panels

High Strength and Durability

Good Air Permeability

Moisture Transport / Water Management

Lab-Scale Prototype Development to Commercial Scale Manufacturing

Produced in US / Caplinq European Agent

Very High Conductivity Porous Graphite Papers / Panels

High Strength and Durability

Good Air Permeability

Moisture Transport / Water Management

Lab-Scale Prototype Development to Commercial Scale Manufacturing

Produced in US / Caplinq European Agent

Spectracarb GDL Technology FocusProvide lower cost products that are

interchangeable with other existing standard grades

Development / Commercial Production of GDL products meeting specific customer requirements / electrochemical applications

Creation of “Next Generation” GDL productsJoint Development / Engineering ProgramsIndependent / Contract Research

China City Bus Program –Fuel Cell Technology

Shanghai Shen-Li Fuel Cell Production

2008 Olympics /2010 World Expo

Spectracarb 2050A-0850 GDL –Good Performance with Lowest Cost

Several Thousand Sheets, 0.2 mm Supplied

Spectracarb 2050A-0850 Properties

Measurement Units Spectracarb2050A-0850

Thickness mm 0.20

Basis Weight g/m2 88

Geometric Density g/cm3 0.44

Mean Pore Size micron 27

Air Permeability, through-plane

cfm/ft2 35

Electrical Resistivitythrough-planein-plane

mW·cm2

mW·cm

185.4

Thermal Conductivitythrough-plane (@

25°C)through-plane (@

100°C)in-plane (@ 25°C)in-plane (@ 100°C)

W/m·K3.43.6

20.724.2

Tensile StrengthMDXMD

MPa 4.22.6

Flexural Strength MPa 37

Flexural Stiffness GPa 9.5

Compressive Strength MPa 2.1

Spectracarb GDL Technology FocusProvide lower cost products that are

interchangeable with other existing standard grades

Development / Commercial Production of GDL products meeting specific customer requirements / electrochemical applications

Creation of “Next Generation” GDL productsJoint Development / Engineering ProgramsIndependent / Contract Research

Porous Graphite Papers/Panels Used in Range of Devices

PEM / PA Fuel CellsRedox Flow Batteries PEM ElectrolyzersHumidifiers Electrochemical Reactors

It Should Not Be Expected That One Material - Or Family of Materials - Will be Optimum for All Applications

PEM Fuel Cell Gas Diffusion Layers (GDL)

Lower Cost (Second Generation) GDL Investigations for Automotive Applications-GM Sponsored

Graphs from MS&T 2009/2011 Conferences –Nicotera et al

Engineered GDL for Improved Water Management

Anode GDL (Higher Diffusion Resistance) Cathode GDL (Standard Construction)

US Patent 8518596 B1 “Low cost fuel cell diffusion layer configured for optimized anode water management” – GM 2013

Vanadium Redox BatteryPorous Electrodes

Redox Flow Batteries

Redox flow batteries (RFBs) are “flow‐through” electrochemical reactors, analogous in many respects to fuel cells Suitable for large scale, stationary energy storage applications (grid storage) Typically aqueous‐based systems: the all vanadium RFB is currently the state‐of‐the‐art (Ecell ~ 1.2‐1.6 V) RFBs feature long cycle life (> 10,000 cycles), and high cell efficiencies RFBs have low energy densities compared to other secondary battery systems (~ 15‐30 Wh/L) Many demonstration units exist world wide; kWh‐MWh capabilities Key feature of RFBs: power and energy density can be mutually exclusive (i.e. decoupled), unlike other 

battery technologies; use larger tanks for higher kWh, and increase the size or number of cells for higher kW

Carbon Electrode Development

Commercial and custom‐made carbon papers and felts are being examined for improved electrocatalyticactivity

Various thermal, chemical, and electrochemical treatments can be used to modify the electrocatalytic activity of carbon electrodes

Unmodified Spectracarb 1550 carbon paper shows improved electrochemical reversibility and catalytic activity when compared to common commercial grade carbon paper used in various RFB systems

RFB performance metrics:CE = td/tc x 100%VE = Vd/Vc x 100%EE = CE x VE

Vanadium Redox BatteryPorous Electrodes

Literature Reference Shows Porous Carbon Papers Have Better Performance than Felts (Q.H. Liu – J. of Electrochemical Society -2012)

Spectracarb 1550 Shows Better Performance than Other Commercial Paper (UKy)

Spectracarb 1550 Being Used as Baseline For Continuing Development / Customer Specific Targets –EFT Program

Reference Also Shows Effect of Thickness (Number of Stacked Sheets of Paper): Suggests Thicker Panels May Increase Performance

Spectracarb 2050A-1550 Properties

Measurement Units Spectracarb2050A‐1550

Sheet size mm 400 x 400

Thickness mm 0.350

Basis Weight g/m2 175

Geometric Density g/cm3 0.50

Air Permeability, through‐plane cfm/ft2 35

Electrical Resistivitythrough‐plane (@ 200 kPa)in‐plane

mW∙cm2

mW∙cm155.4

Thermal Conductivitythrough‐plane (@ 25°C)through‐plane (@ 100°C)in‐plane (@ 25°C)in‐plane (@ 100°C)

W/m∙K3.43.620.724.2

Flexural Strength MPa 40

Porosity % 78

PEM Electrolyzer Cathode Current Collector

Laboratory Electrolyzer with Spectracarb Cathode Current Collectors- Curiosity SINTEF

Spectracarb Panels for Electrolyzer Cathode Current Collectors

Lower Cost Alternative to Titanium Mesh / Sintered Ti

Thicker Plates (Up to 5mm) Higher Density (up to one

g/cm3) Higher Bending Stiffness vs

Stacking of Thin Papers Function as Elastic Springs

in Compression (30%) Machinability Hybrid Constructions

Possible

Spectracarb GDL Panels For Electrolyzer Cathode Applications

Properties- Spectracarb Electrolyzer Panel (12580)- Elastic Springs

0,0

5,0

10,0

15,0

20,0

25,0

0 200 400 600 800 1000

Stra

in, %

Stress. PSI

Percent Strain 1Percent Strain 2

Thin GDL with same requirements as Fuel Cell Except Conductivity / Graphitization Not Necessary

Paper Based on Glass / Ceramic Fiber- High Purity Resin Binder

US Patent 8974977 “Wetside Paper for Fuel Cell Humidifier” GM 2015

Other Specific Designs for Electrochemical ApplicationsHumidifiers for Fuel Cells Electrolyzers for

Chemical Electrolysis Thicker Electrode Panels

Similar to Water Electrolysis with High Flow (HF) –Larger Average Pore Size / Higher Porosity / Low Pressure Drop

US Patent 7341654 “Mediated Hydrohalic Electrolyzers” (2008)

Spectracarb Technology FocusProvide lower cost products that are

interchangeable with other existing standard grades

Development / Commercial Production of GDL products meeting specific customer requirements / electrochemical applications

Creation of “Next Generation” GDL products Joint Development / Engineering Programs Independent / Contract Research

ENGINEEREDFIBERS

TECHNOLOGY

THANK YOU!

Please Visit Us at Stand C40/4 to Discuss Your Specific GDL

Requirementswww.Spectracarb.com