The Capacity
Boosters
Our graphite based
battery solutions
SIGRACELL®
SIGRACET ®

Graphite Materials & Systems

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34
SIGRACELL® materials for batteries
Enhancing energy storage
for tomorrow’s needs
We produce high-quality graphite material for lithium-ion battery anodes
amounting to double-digit thousands of tons each year. Fueling battery gigafactories with our products is our mission. And we are able to scale up volumes
as requested – always maintaining the high performance that characterizes
all of our materials. That’s why our products really are “capacity boosters”
for energy storage systems, which will help usher in the new era of energy.

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GWh

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Our graphite based
battery solutions
With their optimized electrochemical profile andmaterial purity, our materials and products forbattery electrodes meet the highest standards for
quality, efficiency and environmental compatibility.

Lithium-ion batteries

Lead acid batteries

Typical applications• Mobility (automotive, buses, trucks,
forklift trucks)• Consumer electronics(cameras, mobile phones, computers)• Industrial applications (power tools)• Stationary applications (from homestorages to grid-scale systems)• Mobility (starter batteries forautomotive)

Materials made of carbon and graphite• Graphite anode materials• Carbon composite anode materials• Conductive carbon additives• Graphite based solutions forbattery thermal management• Battery housing• Performance and conductive additives

SGL Carbon products• SIGRACELL® specialty graphites• SIGRACELL® synthetic graphite powders• SIGRACELL® expanded graphite powders

The Capacity Boosters | Overview

Our customers benefit from energy storage with increased
performance and reliability in a wide range of applications
across all relevant industries. We provide tailor-made solutions
based on our long-term experience and close development
partnerships, including the option of large-scale production.

Redox flow batteries
Vanadium (VRFB) or
Zink-bromine (Zn-Br)

Proton exchange membrane (PEM)
fuel cells• Stationary applications(from home storage to grid-scale
systems)• E-mobility (automotive, trains, trucks,
buses & forklifts)• Stationary power generation andback-up power• Power chargers for consumer
electronics• Electrodes• Bipolar plates• Gas diffusion layers (GDL)• Separators and bipolar plates• SIGRACELL® battery felts• SIGRACELL® bipolar plates• SIGRACET® carbon paper• SIGRACELL® graphite foils

5

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Products
for lithium-ion
batteries
Thanks to our extensive expertise, we offer thebroadest range of customizable high-quality
products and solutions for lithium-ion batteries.

The Capacity Boosters | Lithium-ion batteries

We are a leading specialist for carbonization and graphitization,
covering every phase from the purchasing of raw materials
to continuously high-quality mass production. Our versatile
process enables us to customize products for a high variety
of application requirements, e.g. for the automotive industry,
stationary energy storage, consumer goods or power tools.
Expertise and innovation
In 20 years of delivering materials at the leading edge oftechnology, we have gained profound expertise in lithium-ion
batteries. At the same time, we strive to strengthen theconnection between research and industry to foster innovation,e.g. in communities devoted to this purpose like the German
Competence Network for Lithium-Ion Batteries (KLIB).
With the state-of-the-art equipment for mixing of slurries
and coating of electrodes as well as for building of two- andthree-electrode pouch, Swagelok and coin cells in our modern
laboratories, we can conduct testing of our tailored materials,
developed to our customers’ specifications. Tests for bothgraphite materials and innovative carbon silicon composites
can be adjusted to customer needs.

Our products for lithium-ion
Unser
Materialportfolio
battery
application• Graphite anode materials• C/Si composites• Additives• Solutions for battery thermal
management• Battery housing

Global presence
SGL is a global top player in synthetic graphite anode materials
for lithium-ion batteries and the only significant western manufacturer. Our sites in Europe and the United States are locatedclose to the production facilities of relevant OEMs and in regionsof planned battery production lines. Our Asian locations are also
close to the main markets of lithium-ion batteries.
Quality and volume
Through decades of experience as a graphite producer, wehave established a sophisticated supply chain benefittingfrom long-term relationships with raw material suppliers.
This allows us to ensure both large volume deliveries andhigh-quality results.

↑ Glove-box for cell building. In our laboratory we produce cells fortesting according to standard and customized protocolls

7

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Graphite anode materials

Advantages of synthetic graphite
Unserover
Material
natural graphite

Backed by decades of experience and reliable, mass and diversified production, we are able to provide synthetic graphite foranode materials at the highest quality level. As a large-scale
producer, we also profit from our highly developed knowledge
and skills along the complete value chain.

• Better cycling stability• Better fast charging
performance• Higher quality consistency

Purity for top-level requirements
We execute graphitization at technically highest possible
temperatures leading to highest purity and optimized productperformance. By our long term experience and know-how in
production process control, we have reduced batch-to-batch
variations to a minimum. Additionally, our high production
capacity and special process design allows us to quickly scale
up delivery volumes. These aspects ensure that our graphite
meets the requirements of high-end applications: performance,
reliability, quality, and safety.

• Faster production scalability

Customization
Our highly versatile production process allows us to influence
various material parameters – from the selection of raw materials to carbonization and graphitization, as well as propertiesof the final product. This enables us to flexibly adapt our products to special application requirements.

We design products with the cost-performance profile
you need
EnergyWith material properties we control electrochemical
battery performances

Premium
Fit-for-purpose

Quality andreliability

PurityParticle
size

Power
Rate
capability

Potential
SafetyEnergydensity

ProcessingPowerdensity

Cycle
life

Cost
BinderVolumeexpansion

BET
Conductivity
Cost optimization

Loading

Chargeacceptance

Efficiency

Processing

Porosity

Cyclingstability

Capacity
SafetyMaterial
Cell/Battery
Electrode

The Capacity Boosters | Lithium-ion batteries

9

Additives for cathodes
We offer a large portfolio of additives based both on synthetic
graphite and processed natural graphite. Due to their highdegree of graphitization, our powders show an extremely highelectrical conductivity which significantly increases theperformance of the battery. Furthermore, the high levelof purity and the surface area control avoid any unwanted
reaction within the cell.

SGL designing material to address customers’ needs↑ REM photos of selected graphite grades

Carbon-silicon composite anode material
Combining favorable properties
Our C/Si composite anode material integrates carefully tailoredsilicon-based materials with our optimized high-performancegraphite anode materials to boost the anode’s capacity beyond
graphite’s theoretical limits. Highly conductive carbon andgraphite allow usage in high-power applications and foster
excellent process ability to electrodes like state-of-the-art
graphite anodes.

Carbon for high performance …
The carbon structure enables an attractive electrochemical
performance profile, such as high coulombic efficiency,
processability and an improved cycle life.
… silicon for energy density and high power
The use of silicon in the anode results in increased gravimetricand volumetric energy density and fast charging capability forour customers, especially when compared to other materials
that meet the requirements for high energy applications.

Improving parameters through C/Si material

Parameter

Capacity
Volumetric energy density
Fast charging capability
Initial coulombic efficiency
Costs
Producibility with existing process

Units

mAh/g
Wh/L
%
€/kWh

SGL Carbon
C/Si composite

Siliconsub-oxides

Siliconalloys

Silicon dominantcomposites

SGL Carbon
graphite

++
++
+
+
+
+

++
+
+
+

+
+
+
○
○
○

++
+
++
○
○
○

○
○
○
+++
+++
+++

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Carbon-based additives
for lead acid batteries
Designed according to the latest research
results, SIGRACELL materials significantly
improve battery performance.

Natural graphite and synthetic graphite

The Capacity Boosters | Lead acid batteries

Performance, conductivity, purity, particle shape
We offer a large portfolio of additives for lead acid batteries
based on synthetic graphite, natural graphite and carbon
fibers. We ensure the best solutions for our customers, withproducts that combine electrical conductivity, high purity
and optimized particle shape.
Excellence through research
Our own focus on research as well as our extensive R&D
network put us at the forefront of material development.
This allows us to integrate the most recent scientific findings
into our production of additives. We provide tailor-made solutions featuring an enhanced dynamic charge acceptance(DCA) in combination with low hydrogen development andimproved cold-crank-ability.

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Key advantages• Significant improvement of DCA• High cycling stability• Very low levels of metal impurities• Excellent wettability• Easy to mix into the lead paste• Combination with conductive
carbon blacks possible

Comparison
Parameter

Units

Material classification
Dynamic Charge Acceptance (DCA)
Cycle life
PurityCosts
Recommended concentration
			

A/Ah

€/kg
wt%

GFG20 HP

SGL Carbon SG

Natural graphite

Synthetic graphite

+++
++
++
+
<3

++
+++
+++
+++
<3

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Graphite-based
solutions forredox flow batteries
We provide reliable components that can beadapted to different requirements – frombatteries for home storage to grid-scaleenergy storage systems with 20 megawatt
hours or more.

Electrolyte tanks belonging to the energy storage system in Pfinztal, near Karlsruhe,each holding 45,000 liters. The 20 MWh system, run by the Fraunhofer Institute for
Chemical Technology and equipped with SGL materials is part of the RedoxWind project
supported by the German federal state of Baden-Wurttemberg and the Federal Ministryof Education and Research. © Fraunhofer-Institut für Chemische Technologie ICTThe Capacity Boosters | Redox flow batteries

Ideal for stationary applications
Redox flow batteries enable energy storage on a scale of
kWh to MWh and provide the perfect solution for stationary
applications. Their main advantage is, that output (MW) andenergy (MWh) can be adjusted independently of one another.
This makes them easily adaptable to the specific requirements at hand.
Expertise for enhanced performance and service life
We rank among the leading manufacturers of specialty graphite components for redox flow batteries. We have applied
our long-term experience and close cooperation with customers to develop our SIGRACELL battery felts, bipolar plates
and endplates. By constantly improving our materials, we
significantly enhance the performance and service life of
our customers’ batteries.

Schematic diagram of redox flow battery
3 2

5

1

2 3

4

5

4

Charge / Discharge

Optimizing performance through felt quality
Inhomogeneity in the battery felt can lead to impermeable
areas that reduce overall system performance. As a result,
we are continuously working on tighter tolerances for thearea weight and thickness of our battery felts. This helps ourcustomers optimize compression rates, thus ensuring thebest possible battery performance.

1 Membrane
2 Permeable electrode
3 Bipolar plate

4 Storage electrode
5 Electrolyte

4
3

2
1

Specialty graphites for redox flow batteries

2
3

Applications

Permeable electrodes
Bipolar plates

SIGRACELL
battery felts

SIGRACELL bipolar
plates and end-plates

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4↑ Flow battery components
1 Ion-exchange membrane
2 SIGRACELL battery felt

3 Flow frame
4 SIGRACELL bipolar plate

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SIGRACELL® battery felts↑ SIGRACELL carbon and graphite felts. We customize to your needs.
Please contact us for details

Ideal properties for an efficient charge exchange
Permeable electrodes made of SIGRACELL carbon and graphite
felts are the first choice for high-temperature batteries likeredox flow batteries. Our felts are used for anodes as well ascathodes. Thanks to a unique combination of electrical conductivity, electrochemical stability, high porosity and goodelasticity, they facilitate an efficient charge exchange between
the electrolyte and the bipolar plate.

Felt activation for enhanced performance
As graphitized felts are non-wetting towards aqueous electrolytes, activation is strongly recommended in order to avoid
slowdown of charge transfer and large resistances. We offer
felt activation through thermal surface oxidation. This treatment induces wettability by generating hydrophilic surfacefunctions while preserving the structural integrity of the fibers,
since the burn-off only affects a few percent.
Adaptable sizes – including large-scale needs
The sizes we provide are even enough to cover the needs oflarge-scale redox flow systems. We supply battery felts instandard sizes up to 1350 mm (53") in width in 25 m (82 ft) rolls.
Beyond that, we produce carbon and graphite felts in customerspecific dimensions.

Ensuring quality – our complete in-house value chain

Fibers→ PANOX®
→ RayonRaw
felt

Carbonizing

Carbonbattery
felt

Graphitizing

SIGRACELL KFD

Graphitebattery
felt

Activation

SIGRACELL GFA
SIGRACELL GFD

Activatedbatteryfelt

Post
treatment/
Cut-to-size

Thermally activated
SIGRACELL

Felt comparison

Typical properties

Fiber precursor
Chemical resistivity
Low area-specific resistance —I ¹⁾
BET surface area
Compressibility
Total impurities
Costs

Carbonized felts
e.g. KFD2.5

Graphitized felts
e.g. GFA3.0

Graphitized felts
e.g. GFD4.6

Thermally activatedgraphite felts
GFA3.0 activated

Thermally activatedgraphite felts
GFD4.6 activated

PAN
○
–
○
+
–
+++

Rayon
++
++
○
++
+
++

PAN
+++
++
○
+
+++
+

Rayon
++
+++
++
++
+
+

PAN
+++
+++
+++
+
+++
○

¹ ⁾  —I vertical to longitudinal direction of felt					The Capacity Boosters | Redox flow batteries

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SIGRACELL® bipolar plates
and end plates
Resistance to chemicals meets high conductivity
The main features that distinguish expanded natural graphite
are exceptional resistance to chemicals and good electricalconductivity. Together with high-grade fluoropolymers, ourthin, high-density SIGRACELL bipolar plates can be used fora broad spectrum of applications. Thanks to their great resistance to corrosion, they are ideally suited for the demanding
cell chemistry in battery systems.

↑ SIGRACELL bipolar plates made of expanded graphite (TF6/PV15)

Bipolar plates (BPP) comparison
Typical properties

Explanation
Process ability
Electrical conductivity
Surface tolerance
Costs
					

Extruded
BPP

Polymercomposite
+++
○
–
+++

Injection molded
BPP

Polymercomposite+++○+

Hot-pressed
BPP

SGL Carbon
bipolar foil

SGL Carbon
graphite BPP

Polymercomposite+++–○

Expanded graphite
based bipolar foils
SIGRACELL TF6
and PV15
+++
++
++
○

Machined
extrudedgraphite –resin impregnated
–
+++
++
–

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Carbon-based
products forfuel cells
Our SIGRACET® gas diffusion layers (GDL) excel
in performance, durability and adaptability todifferent applications.

SIGRACET gas diffusion layer

The Capacity Boosters | Fuel cells

Gas diffusion layers (GDLs) are key components of proton
exchange membrane (PEM) fuel cells. They modulate all
relevant transport processes concerning reaction products,
electricity and heat.
Designed for high performance
Our high-performance products are the result of continuous
research. We tailor their material properties to meet therequirements of the intended application. Our customers
benefit from our know-how in fine-tuning the physical andelectrochemical attributes of our materials to optimize theirinteraction with other cell components.

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Selection of non-fuel cell applications andrecommended SIGRACET ® grades
Material applied as

Recommended grade(s)Redox flow batteries

Porous electrode forzero-gap cell design

GDL 39 AA/38 AA

Metal-air batteries

Cathode support(for GDE)Electrode support
Cathode support

GDL 39 AA/BC
GDL 39 AA/BC
GDL 39 AA/BA/BC

Applications

Microbial fuel cells
PEM electrolysis

Great variety
Thanks to our sophisticated production process, we can offera broad range of GDLs with variable thickness and porosity,each suited for a specific set of applications based on its
physical attributes. Our portfolio has an extensive selectionof GDLs for dry or wet operating conditions, based on theirelectrochemical attributes. For example, GDLs for dry
conditions are designed to prevent membrane dehydration.
We also offer solutions if high gas diffusivity is needed.
Other applications
Our GDLs can also be used in electrochemical applications,such as redox flow or metal air batteries as well as for microbial
fuel cells and PEM electrolysis.

PEM

Preferred SIGRACET ® grade for various applications
Applications

GDL 28GDL 29GDL 38GDL 39200 µm200 µm300 µm300 µmLow
porosityHighporosityLowporosityHighporosity

PEMFC
stationary
PEMFC
automotive
PEMFC
portable
HT-PEMFC
DMFC
PEM
electrolysis

Backing MPL
GDLCatalyst↑ Structure of a PEMFC single cell

Flowfield

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SIGRACELL® and SIGRACET®
in relevant industries
Our materials are widely used in a broad range
of industries, helping to enhance energy storage
and achieve more sustainable solutions.

Segment

E-mobility

ExamplesCars, buses, trucks, trains, forklift trucks and others

Application example

Electrical propulsion and fuel cell

Start-stop battery

Products with our material

Li-ion batteries

PEM Fuel cells

Advanced Pb-acidbatteries

Our input• Artificial graphite foranodes• Carbon-silicon composites
for anodes• Graphite additives• Solutions for battery
thermal management• Battery housing• Gas diffusion layers• Bipolar plates• SIGRACELL® additives fromprocessed natural andartificial graphite

Our impact on the products• Higher energy density• Improved C-rate• Higher stability and safety• Higher cell performance• Various explicit productattributes• Improved dynamic charge
acceptance (DCA)• Reduced hydrogen
evolution

Advantages of our materials• High purity• Stable quality• Customized cost/
performance• High production capacity• Stable quality andperformance depending
on application needs• High conductivity and purity• Stable quality and highperformance

The Capacity Boosters | Markets

Stationary storage solutions

Other mobile devices

Consumer products

Energy storage systems

Power tools, bicycles andothersMobile phones, notebooks

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Stationary power wall

Electrical stationary
storage (ESS)Electrical propulsion

Battery

Li-ion batteries

Redox flow batteries

Li-ion batteries

Li-ion batteries• Artificial graphite foranodes• Carbon-siliconcomposites
for anodes• Graphite additives• Bipolar plates, carbon andgraphite felts• Artificial graphite foranodes• Carbon-silicon composites
for anodes• Graphite additives• Artificial graphite foranodes• Carbon-silicon composites
for anodes• Graphite additives• Higher energy density• Improved C-rate• Higher stability and safety• Tight specification
tolerances enabling beststack sealing• Higher energy density• Improved C-rate• Higher stability and safety• Higher energy density• Improved C-rate• Higher stability and safety• High purity• Stable quality• Customized cost/performance• High production capacity• Homogeneous productquality• Conductivity• Power capability• High volume production
capability• High purity• Stable quality• Customized cost/
performance• High production capacity• High purity• Stable quality• Customized cost/
performance• High production capacity

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Successful
togetherLithium-ion batteries are complex electrochemical systems involving dozens ofcomponents, all of which react with eachother. Changing a single property of justone component can lead to a significant
change in the entire cell.
This is why it is so crucial to test ourmaterials according to our customers’
specifications. Our laboratory meets thisneed and provides full characterization of
the materials under different conditions.
We also carry out further tests in collaboration with universities and research
institutions.
As a result, we can deliver material witha characterization that is as close as possible to our customers’ own characterization, helping to accelerate development
and upscaling processes at customers’end.

The Capacity Boosters | Successful together

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A laboratory for
tailor-made solutions
Special tests
We test according to the conditions of our customers.
Adjusting the electrode recipe
We adjust our standard electrode recipe to match theones used by our customer.
Testing of properties
We test the properties of electrodes (e.g. adhesion
and cohesion, particle orientation, wetting, SEM)
according to customer specifications.
Use of same cathode type
We can use a cathode type identical or similar to
those of our customers.
Adapting electrolyte and additives
We apply an electrolyte composition and/or additives
identical or similar to the ones of our customers.
Variable test conditions
We can change the electrochemical characterization
test conditions (e.g. C-Rate, cycling type, cycling
temperature, storage condition, etc.) according toour customers’ requirements.
Measuring swelling and gas
We measure the swelling of the electrodes and thegas development in a pouch cell.
Pouch, Swagelok and coin cells
Our cutting-edge equipment also enables us to build
two- and three-electrode pouch, Swagelok and coincells.

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Smart
Solutions
Be it materials, components or production
processes, we focus our thinking and actions on
the customer and keep an eye on the big picture.
Our solutions already anticipate the future today.
The following examples show a selection of ourunique product range.

Mobility• Lightweight components and structural parts
based on fiber-reinforced composites for automotive and aerospace manufacture• Graphite anode material for lithium-ion batteries
in electric vehicles• Carbon-ceramic brake disks for sports cars andluxury sedans

Energy• High-temperature solutions based on specialty
graphites and fiber materials for the photovoltaic
industry• Carbon fiber materials for rotor blades• Gas diffusion layers for fuel cells• Systems for more efficient heat exchange andheat recovery• Carbon fibers for pressurized gas containers

Digitization• Carbon, graphite, and CFC components forpolysilicon and monocrystal pulling in thesemiconductor industry• High precision, coated graphite carriers for the
production of LEDs

→ State-of-the-art green production withthe world’s largest isostatic press

SGL Carbon

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SGL Carbon
We are leaders in the development and manufacture of products based on carbon, graphite,
carbon fibers, and fiber-reinforced composites.
In partnership with our customers, we develop
intelligent, trendsetting, and sustainable
solutions that deliver a clear benefit.
With our in-depth material, engineering, andapplication know-how, we make a substantial
contribution to the major future topics mobility,
energy, and digitization.

Contact
Europe / Middle East / Africa
SGL CARBON GmbH
Soehnleinstrasse 865201 Wiesbaden/Germany
sigracell-europe@sglcarbon.com
Americas
SGL CARBON LLC
307 Jamestown Road
NC 28655 Morganton/USA
sigracell-americas@sglcarbon.com
Asia / Pacific
SGL CARBON Far East Ltd.
No.151, East Huan Cheng Road
Fengxian district
201 401 Shanghai/China
sigracell-asia@sglcarbon.com®

registered trademark of SGL Carbon SE

This information is based on our present stateof knowledge and is intended to provide generalnotes on our products and their uses. It should
therefore not be construed as guaranteeing
specific properties of the products describedor their suitability for a particular application.
Any existing industrial property rights must be
observed. The quality of our products is guaranteed under our “General Conditions of Sale“.

02 2020/1 2N Printed in Germany

Graphite Materials & Systems
SGL CARBON GmbH
Soehnleinstrasse 865201 Wiesbaden/Germany
www.sglcarbon.com/gms