What does the lignin do in a lead battery?

The lignosulfonate affects the crystal size, pore structure, and external surface area of the negative electrode

It is also believed to impede and disrupt formation of a lead sulfate passivating layer upon discharge, prolonging battery cycle life. However, active research is ongoing to better understand and quantify the effect lignosulfonates have on the physical structure and reactivity observed in lead battery grids.

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