Lignosulfonate is one of the classic ingredients of lead-acid batteries. A small amount goes into the negative plate as part of the expander, where it helps the sponge lead keep its surface area over many charge and discharge cycles. This page explains its role, what battery makers check in a lignosulfonate, and how to qualify calcium lignosulfonate Grade One for this use.
- Where it goes: negative-plate paste, as the organic part of the expander.
- Partners in the expander: barium sulfate and carbon black.
- What it supports: low-temperature and high-rate discharge, and stable plate structure during cycling.
- Listed grade: calcium lignosulfonate Grade One (GAC-CaLS-1).
How Lignosulfonate Works in the Negative Plate
During discharge, the sponge lead of the negative plate turns into lead sulfate; on charge it turns back into lead. Without an expander, the lead tends to recrystallise into a denser structure with less active surface, and the plate loses capacity, particularly at low temperature and high discharge rates.
Lignosulfonate adsorbs on the lead surface. It influences how lead sulfate crystals form and dissolve and helps the lead stay finely divided. The Green Agrochem Grade One TDS describes this as improving the crystallisation of lead sulfate in negative plates.
| Expander component | Main function |
|---|---|
| Lignosulfonate (organic) | Adsorbs on lead; helps maintain a fine, porous sponge-lead structure |
| Barium sulfate | Nucleation sites for lead sulfate during discharge |
| Carbon black | Electrical conductivity in the plate |
What Battery Makers Check in a Lignosulfonate
| Property | Why it matters | Grade One TDS value |
|---|---|---|
| Lignosulfonate content (dry basis) | Active organic content per kg of expander | 55% min |
| Water-insoluble matter | Foreign solids in the paste | 1.5% max |
| Moisture / dry matter | Accurate dosing in paste mixing | 5% max / 95% min |
| Ash | Inorganic content added to the plate | 12% max |
| Total calcium and magnesium | Counter-ions added to the paste | 5–8% |
| Metal impurities | Some metals can increase gassing and self-discharge | Agree limits and test per lot |
Values are typical and from the current TDS (Rev. 2.0). Batch results are stated on the certificate of analysis.
Qualifying Calcium Lignosulfonate for Battery Use
- Agree the specification, including impurity limits and test methods, before samples are sent.
- Prepare expander blends with the candidate and with the current reference lignosulfonate, keeping barium sulfate and carbon constant.
- Build test cells or batteries on the normal paste and curing line.
- Compare low-temperature cranking, charge acceptance and cycle life under the battery maker’s own test standard.
- Check lot-to-lot consistency on at least three production lots before approval.
Limits to Keep in Mind
- Lignosulfonate is an organic material and can degrade over time at elevated operating temperatures, so high-temperature applications need their own testing.
- Natural lignosulfonates vary with wood source and process. Fix the grade and source once a formulation is approved.
- Industrial grades are documented for industrial use; follow the battery maker’s own approval process.
Lead-Acid Battery Expander: FAQ
What does lignosulfonate do in a lead-acid battery?
It is the organic part of the negative-plate expander. It adsorbs on the lead surface and helps keep the sponge lead finely divided during charge and discharge, which supports low-temperature and high-rate discharge performance.
What else is in a negative-plate expander?
Expanders are usually a blend of an organic component such as lignosulfonate, barium sulfate, which acts as a nucleation site for lead sulfate, and carbon black, which improves conductivity. Each battery maker sets its own formulation.
Which calcium lignosulfonate grade is listed for batteries?
Green Agrochem Grade One (GAC-CaLS-1). Its TDS lists use as an active material in lead-acid battery negative plates. It has 55% min lignosulfonate content on a dry basis and 1.5% max water-insoluble matter.
How is a new expander lignosulfonate qualified?
By building test cells or batteries with the candidate and a reference expander, then comparing cold-cranking, charge acceptance and cycle life under the battery maker’s own test standard. Impurity limits, especially for metals, are agreed before the trial.
Grade, Documents and Samples
Specification, TDS and MSDS for Grade One: calcium lignosulfonate (CAS 8061-52-7). Other industrial uses and grade selection: calcium lignosulfonate uses and grades. For samples and a COA, contact us through the contact page with your expander formulation and test plan.
