Lignosulfonate, a lead battery additive produced from wood pulp, is a cost-effective solution used to improve discharge capacity from the negative electrode. It is in a complex reaction with lead and lead sulphate, reducing the size of unwanted PbSO4 crystals. The crystals shorten the expected operational time of the electrode.
Researchers will examine the molecular structure of lignosulfonates as part a joint research project initiated by the American Battery Research Group (ABRG) in cooperation with the Department of Energy’s Argonne National Laboratory and the University of Toledo.
The two-year programme aims to free the untapped potential of conventional lead batteries.
The lignosulfonate-based additive, containing for example barium sulfate, coal and lignosulfonates or other comparable organic materials, will also improve resistance to high temperature degradation, a weak point for standard lead batteries. However, a significant side-effect of the paste is that the recharging rates are limited. This will reduce the lifespan of the lead battery.
As is often the case with lignosulfonates, the undefined molecule structure and the presence of too many organic functional groups cause problems when tailoring nature-based expanders for the lead battery chemistry.
The project is financially supported by five US lead battery manufacturers: Clarios, Crown Battery, East Penn Manufacturing, Ecobat and EnerSys.
The problems with varying quality and diffuse structure of natural lignosulfonates can be avoided by high-precision synthesis of substances that enhance reactivity of the negative electrode.
These synthetic expander long-chain materials should offer better electrochemical stability, thus improving both discharge and charge properties. The new model expander molecules will be evaluated by industrial partners in actual batteries.
This project supports the US federal initiative to strengthen domestic supply chains for critical products.