Specific surface area (BET) is often used as a proxy for conductivity performance. However, in lead-acid batteries, conductive additives with extremely high BET surface area frequently lead to poor cycle life and unstable performance.
In lead-acid systems, conductive additives must maintain electronic pathways while operating in a highly acidic environment and under repeated volume changes of active material.
High BET materials dramatically increase the electrode–electrolyte interface, accelerating parasitic reactions and water loss in lead-acid batteries.
Highly porous, high-BET additives often collapse or lose effective contact during cycling, breaking conductive pathways over time.
Additives that form stable, long-range conductive networks at low loading—without excessive surface area—offer better long-term performance in lead-acid batteries.
For lead-acid batteries, conductive network stability and chemical compatibility are more important than maximizing BET surface area.