1. King Mongkut’s University of Technology Thonburi
Effects of Carbon black and Sodium lignosulfonate in Expander on Capacity of Lead Electrode
Somsak Meenakorn
Integrated Product Design and Manufacturing School of Energy, Environment and Materials,
King Mongkut’s University of Technology Thonburi
Good afternoon ladies and gentlemen, my name is Somsak Meenakorn from …
I would like to present my paper, in the title of “… “

2. Outline Introduction Objective Methodology Results and Discussion
Conclusion
In my presentation, I will start with introduction then, objective, methodology, results and discussion and conclusion.

3. Introduction Structure of Traction Battery Traction Battery
Service Life
Capacity
Active Materials
Expander
It is well known that traction batteries are rechargeable batteries.
They are used as power sources for various types of vehicles such as forklifts, wheelchairs, ships and subway trains.
The structure of traction battery is shown in this picture.
Service life of the batteries depends on their capacity and battery degradation during charge-discharge cycle.
Capacity of each battery relies on composition of active materials.
They consist of lead oxide, dynel flock, sulfuric acid, water, vaseline and expander.
An expander is a mixture of barium sulfate, sodium lignosulfonate and carbon black.
Function of expander is to increase discharge rates and cyclability.
Barium Sulfate
Lignosulfonate
Carbon Black
Structure of Traction Battery

4. Introduction (cont)
Structure of Carbon Black on the Electrical Conductivity
Carbon black in the expander is used to improve conductivity of the active materials during deep discharge.
Generally, carbon black can be classified by its structure as low, medium and high structure.
A low-structure carbon black refers to an aggregate of a relatively few carbon black primary particles.
In contrast, high structure carbon black is an aggregate consisting of many primary particles with considerable branching and chaining.
In general, the recommended amount of carbon black in an expander is equal to that of lignosulfonate.
However, the effects of both carbon black and lignosulfonates on capacity of traction battery are still unclear.
Low Structure
High Structure

5. Objective
This study aims to study the effects of carbon black and sodium lignosulfonate in expander on capacity of lead electrode.
From mentioned problems, this study aims to …

6. Sodium lignosulfonate
Methodology
Materials
The designation of the prepared expander
Batch Name
Weight ratio
Barium sulfate
Sodium lignosulfonate
Carbon
black
XE8844 88 4
XE8864 6
XE8846
XE8866
XE8886 8
XE8868
XE8888
In this study, we used XE2B which is high-structure carbon black.
A commercial expander namely HE115 was also used in this study as a reference.
Expander was prepared by mixing barium sulfate, sodium lignosulfonate and carbon black by a bench-top high speed mixer.
The expander composition and designation of all samples were shown in the table.
For example, the XE8844 consists of barium sulfate to lignosulfonate to carbon black in the weight ratio of 88:4:4, prepared at mixing speed of 500rpm and mixing time of 2 minutes.

7. Transmission electron microscope (TEM)
Methodology (cont)
Testing
Mixing Expander
Cyclic voltammetry
Electrode : Pure lead
Reference : Ag/AgCl
Counter : Pt
Electrolyte : Sulfuric acid
Start potential (v) : -0.90
Step potential (v/s) :
Transmission electron microscope (TEM)
After preparing the expander, they are tested with cyclic voltammetry and TEM

8. Results and Discussion
Effect of sodium lignosulfonate on amount of charge is shown in this slide.
For this series of experiment, the amount of barium sulfate and carbon black in expander were kept constant at the weight ratio of 88 and 6, respectively.
This figure indicates that the amount of charge when the weight ratio of lignosulfonate in the expander is at least 6 is higher than that when HE115 was used.
To explain the effect of lignosulfonate on capacity, the function of each ion in lignosulfonate must be understood.
When lignosulfonate is added in an expander, lignin anion will adsorb on the surface of the lead particles.
The sulfonate cation, in addition, faces out to the aqueous electrolyte.
This phenomenon causes an increase in the repulsion potential between lead particles.
Therefore, capacity of negative active materials increases.
Amount of charge of the anodic peak and number of cycles for a pure lead electrode in 1.25 g cm-3 density sulfuric acid containing 20 ppm of a) XE8886, b) XE8866, c) XE8846 and d) HE115 (commercial expander)

9. Results and Discussion (cont)
The images from transmission electron microscope (TEM) of HE115 and XE8866 are shown in this page.
From the figure, the black aggregate, the gray cluster and the light-gray cluster are barium sulfate, carbon black and sodium lignosulfonate, respectively.
Sodium lignosulfonate is chained by carbon black aggregate, calling lignosulfonate-carbon black cluster.
Right figure shows that the branch of aggregate in XE8866 is longer than that found in HE115.
Therefore, expander containing XE8866 has higher surface area.
Images from transmission electron microscope (TEM) of (a) HE115 and (b) XE8866

10. Results and Discussion (cont)
Although lignosulfonate increases capacity, the effect of amount of lignosulfonate on increasing capacity is limited at the weight ratio of 6.
Further increasing lignosulfonate results in a small decrease of capacity.
The capacity reduction may be explained by oversaturation.
Excess lignin anions may increase the thickness of lignin layer on surface of lead particle and then hinder the charge transfer.
Amount of charge of the anodic peak and number of cycles for a pure lead electrode in 1.25 g cm-3 density sulfuric acid containing 20 ppm of a) XE8886, b) XE8866, c) XE8846 and d) HE115 (commercial expander)

11. Results and Discussion (cont)
Effect of carbon black on amount of charge is shown in this slide.
For this series of experiment, the amount of barium sulfate and sodium lignosulfonate in expander were kept constant at the weight
ratio of 88 and 6, respectively.
This figure indicates that the amount of charge when the weight ratio of carbon black in the expander is at least 6 is higher than
that when HE115 was used.
To explain the effect of carbon black on the amount of charge, an increase of carbon black enlarges a conductive network on lead
electrode.
This network prevents isolation of active materials by lead sulfate and facilitates charging of battery.
It is also found that an increase of carbon black retards the lead sulfate formation on the surface of negative electrode.
The accumulation of lead sulfate on the electrode surface decreases of electrical conductivity as well as capacity.
Therefore, the amount of charge resulted by an increase of carbon black is limited at the weight ratio of 6.
Amount of charge of the anodic peak and number of cycles for a pure lead electrode in 1.25 g cm-3 density sulfuric acid containing 20 ppm of a) XE8868, b) XE8866, c) XE8864 and d) HE115 (commercial expander).

12. Results and Discussion (cont)
The comparison of amount of charge when the weight ratio of sodium lignosulfonate is equal to that of carbon black and the weight ratio of barium sulfate is 88 is shown in this page.
From this figure, the increases of both lignosulfonate and carbon black increases amount of charge and the maximum charge was obtained after approximately 200 cycles.
Then amount of charge decreases gradually.
In addition, cycle chargeability after 300 cycles for XE8866 case is better than that in case of XE8888 was applied.
Therefore, the appropriate weight ratio of barium sulfate: lignosulfonate: carbon black is 88:6:6.
Amount of charge of the anodic peak and number of cycles for a pure lead electrode in 1.25 g cm-3 density sulfuric acid containing 20 ppm of a) XE8888, b) XE8866, c) XE8844 and d) HE115 (commercial expander)

13. Conclusion It was found that
The results showed that carbon black and sodium lignosulfonate enhances capacity and cycle chargeability of the electrode.
The highest capacity is found when the amount of carbon black is equal to that of lignosulfonate.
The maximum amount of charge and the best cycle chargeability are obtained when the weight ratio of barium sulfate to lignosulfonate to carbon black is 88:6:6.
This is my conclusion …

14. Acknowledgements Metrohm Siam Ltd
The National Metal and Materials Technology Center
Defense Industry and Energy Centre, Office of the Permanent Secretary for Defense, Ministry of Defense
For this research, I would like to thank ….

15. Thank you for your attention