Carbon black provides extra conductivity, facilitating control of the concentration of PbSO4 along the surface of the NAM by charge transfer and dissolution; carbon aerogel may improve this function by decreasing sulfation. Carbon aerogel was first synthesised using a polymerisation reaction to evaluate this advantage. The resulting gel material was dried, revealing a highly porous structure, and then introduced with expander blends into the NAM. To assess the different expanders with varying contents of carbon aerogel, a technique based on cyclic voltammetry was used, where the electrolyte was prepared by dissolving the expanders and then a lead electrode immersed in the electrolyte was cycled within the potential range of -0.325V to -0.725V. In the PbSO4│Pb electrode, the expander impedes the process of PbSO4 reduction and typically decreases the charge acceptance. Carbon aerogel increases this effect with its high surface area and supercapacitive effect in NAM, which improves overall conductivity.
Additionally, 2V single-cell batteries were made without and with 5% and 10% carbon aerogel in their NAM expander and were tested according to IEC 60095-1-2018 standard. Results show 3.5 to 10.8% improvement in C20, 10.5 to 15.8% improvement in CCA, and 39.6 to 47.8% improvement in charge acceptance tests. The water consumption of the batteries remains almost constant, and carbon aerogel can increase lead-acid battery charge acceptance with no adverse effect on water consumption.