LABAT’2017

June 13-16, 2017

How to Develop Best Graphite Products for Lead-Carbon Battery Applications

Dr. Joseph Li Dr. Francois Henry

Dr. Yujie Feng

Superior Graphite Co.

• Ownership- Family-owned & Partial ESOP • Since 1917- Providing carbon-based solutions • Employees- 260 globally • Turnover> $100M- >35% non-North American sales • Operations- 5 production sites; 2 R&D facilities • ISO 9001:2008 Certification- USA and Europe; ISO

14001:2004- Europe

Europe Headquarters, Sundsvall, Sweden Plants, Sundsvall, Sweden

World Headquarters, R&D, Chicago, Illinois Plants, Bedford Park, Illinois

Offices Höhr-Grenzhausen, Germany

Plant Russellville, Arkansas

Plants Hopkinsville, Kentucky

Office Shanghai, China

Locations

Classification of Carbon & Graphite

Unstructured Carbons Coke Carbon Black

Petroleum Coke

Pitch Coke Activated Carbon

Nanotubes

3D Structure ---Diamond

Graphene

Graphite

Macro-crystalline

Micro-crystalline Natural Flake

Vein

Synthetic Primary

Secondary

2D Structure

Applications of Graphite in Energy Storage Characterization of Graphite

Primary and Secondary Properties

• Performance additives in Advanced Lead-acid battery

• Anode Materials in Li-ion Battery • Conductive additives

• Alkaline battery, • Li-ion battery • Li-FeS2 battery • Li-MnO2 battery • Zn-Air battery • NiCd battery • Others

• Bipolar plate materials in Fuel Cells • Others

Typical Applications

Hexagonal structure with three dimensional

ordering.

High Purity Graphite Needed for Advanced Batteries

From J. Hu, etc. Int. J. Electrochem. Sci., 11 (2016) 1416-1433

Example: Graphite in advanced Lead acid battery applications: Graphite with high impurities show significant higher gassing

Carbons in negative plates

Carbon contents

Fe Cu Sb Mn Co Ni Expanded Graphite#1 1.50% 2370 56 ★ 53 ★ 23Expanded Graphite#2 1.50% 340 29 ★ ★ ★ ★ Expanded Graphite#3 1.50% 21 ★ ★ 28 ★ ★ Note: ★: metal impurity content ＜10 ppm.

Metal impurity contents / ppm

Purification Technologies

• Chemical Purification Technologies (e.g., acid leaching technology): Remove impurities including metallic elements with high concentration of either of acids

(HCl/HF/H2SO4) or alkaline salts Simplest form of purification and Economical Potential chemical residues in graphite Environmental concerns

• Thermal Purification Technologies:

Remove impurities including sulfur and metallic elements; Decomposition and carbothermic reduction of impurities/metal oxide. Impurity vapor diffuse outward between the cleavage planes of carbon and carried out by

fluidized bed furnace flue gas.

Thermal Purification Technologies

Acheson Process Horizontal process Moderately efficient High-purity Environmentally not unproblematic

Conductive Graphite Core

Coke Graphite SiC + SiO2 + C SiC

SiO2 + C SiO2 + SiC + C

Removable Side Wall

Superior Graphite EFB Technology

Vertical process flow High throughput High-purity Environmentally friendly

• Continuous processing capability • Consistent quality • Precise control of the process • Ultra-high Purity - +99.95% C • Improved conductivity • Economic effectiveness • Purify a wide range of carbons; Natural and synthetic graphite Carbon black Coke variants

SG Electro-thermal Fluidized Bed (EFB) Technology

Thermal Purification at Superior Graphite

Flake graphite extracted from ores and further upgraded to 95+% carbon

Thermally Purified flake upgraded to 99.9+ % carbon

Thermal

Purification

CeylonCanada

ChinaMozambique

Fe Content After Purification

Fe content before purification

5000

3300

450

3756.3

1619

10

0

1000

2000

3000

4000

5000

Fe C

onte

nt, p

pm

Source of the Natural Crystalline Graphite

Fe Content After Purification Fe content before purification

Effects of EFB Purification Process

market available products

Elements SymbolRaw

material (ppm)

EFB Purified (ppm)

Chemical Purified

599.95 (ppm)Aluminum Al 1570.3 5.6 7.0Arsenic As 4.5 <1.0 <1.0

Chromium Cr 0.7 <1.0 <1.0Cobalt Co 0.7 <1.0 <1.0Copper Cu 13.9 <1.0 <1.0

Iron Fe 2444.9 26.5 115.0Lead Pb 1.7 <1.0 <1.0

Molybdenum Mo 24.9 2.2 <1.0Nickel Ni 1.9 1.5 <1.0

Vanadium V 1.4 1.2 <1.04064.9 37.0 122.0Total

Applications in Lead-carbon Batteries

• Significant Cycle Life Improvement; • Improving dynamic charge acceptance; • Slow down internal resistance increase;

+ -

PbO2 Pb

Traditional Lead-acid Battery

Lead-Carbon Battery for Start-Stop Technology

+

PbO2

Pb with graphite /carbon

-

Carbon/Graphite

Carbon/Graphite Properties and Effect on Battery Performance.

• Electrical conductivity It is one of the most important carbon characteristics. Carbon conductivity is the parameter that allow it to work as conductive bridge among the numerous lead sulphate crystals that develop during battery operation at partial state of charge like in HEV use. Influence of conductivity is clearly seen on high rate discharges at low temperature in which it counteract the deleterious effect of distortion of lead structure caused by carbon addition. Other aspect with high influence of carbon conductivity, is the performance on cycle life. When adding high conductive graphite like expanded graphite or conductive carbons, a noticeable and consistent increase of cycle life is obtained.

• Specific Surface Area This is a carbon parameter directly related with battery charge acceptance. Charge acceptance have an almost direct relation with the SSA of the carbon added. The positive effect of carbon SSA, is also seen on cycle life. As a consequence of increased charge acceptance, the battery is capable of accepting charge in a more efficient way markedly improving the performance on cycle life, but could cause potential high gassing.

• Particle size It is directly related with the degree of distortion of the lead structure. The lower the particle size, the lower the distortion. Its effect has been tested on project 1012M in which working with pre-dispersed graphite, very high durations on High Rate Low temperature were obtain.

21-Jun-17/MTW 14

•Milling and Processing of high Purity Flake Graphite With a Variety of Processing Systems •Dry Blending of Graphite with Non-conductivity Material at Various Concentrations •Determination of Resistivity under Constant Load by Means of Two Point Method

High Purity Flake Graphite >99.9%C, Lc>300 nm

Hammer Milling Air classic Milling Fluidized Bed Milling Exfoliation /Air milling Super Exfoliation /Air milling

Blending With Non-conductivity Material MnO2

Measurement of Electrical Resistivity

Effects of Processing Technologies on Graphite Properties Concept of Investigation

Mill and Processing Technologies Hammer Milling Air Classic Milling

Sample 1 Sample 2

Mill and Processing Technologies (Cont.) Fluidized Bed Milling

Sample 3

Exfoliation/Expansion Air Milling

Sample 4

Physical Properties in Summary

Product Type of Milling Particle Size d50 (micron)

Bulk Density (g/ccm)

SSA BET (m2/g)

Sample 1 Hammer Milling ~ 10 0.16 ~ 9Sample 2 Air Classic Milling ~ 10 0.09 ~ 7Sample 3 Fluidized Bed Milling ~ 10 0.06 ~ 9Sample 4 Exfoliation/Air Milling ~10 0.05 ~ 20Sample 5 Super Exfoliation/Air Milling ~10 0.045 ~ 23

Electrical Resistivity vs. Processing Technologies

Commercial Available Products

SG Product Portfolio – for Lead-acid Batteries FormulaBT® for

Lead-acid Batteries Negative Active Materials Additives

FormulaBT® ABG1010 Expanded Natural Graphite

FormulaBT® ABG1025 Expanded Natural Graphite

FormulaBT® LBG8004 Purified Natural Graphite

FormulaBT® 2939APH Purified Flake Graphite

FormulaBT® ABG1045 Expanded Natural Graphite

FormulaBT® ABG1010

FormulaBT® LBG8004

FormulaBT® 2939APH

FormulaBT® ABG2010 Super ExpandedNatural Graphite

FormulaBT® ABG2010

Power Assist Cycle Life

From M. Fernández, J. Valenciano, F. Trinidad, N. Mu˜noz, Journal of Power Sources 195 (2010) 4458–4469, project funded by ALABC

Effects on Cycle life improvement by graphite type

EG - expanded graphite; SG - synthetic graphite FG – flake graphite; CCB – conductive carbon black

End of discharge voltage and electrical resistance

Discharge Power vs. SoC (6V 10Ah modules) ABG1010 improved high rate low temperature discharge power

From Exide research group at Spain (Melchior Fernandez), project funded by ALABC

1.5% ABG1010 1% CB1+1% ABG1010 1% CB2

Summary

• Graphite properties, e.g. purity, electric conductivity, specific surface area as well as particle size, have significantly effects on Lead-acid battery performance.

• Superior Graphite’s Electro-thermal Fluidized Bed (EFB) technology has been demonstrated to be the most capable and efficient route to purify carbon and graphite materials for advanced battery applications.

• Processing technologies have large effects on graphite properties.

• Expanded (exfoliated) graphite products, produced with SG’s EFB technology, show high purity, excellent electric conductivity and high specific surface area, and best suitable for Lead-carbon battery application.

Thank You for Your Attention