Development and Characterization of Advanced Electrode Materials for Lead Acid Batteries, both AGM and Flooded technology

Battery-based energy storage systems with high power and energy density play a crucial role in our daily lives. Although LABs are often considered outdated technology, they still dominate the global market due to their simple design, low cost, ease of manufacturing, and efficient recycling processes. However, LABs face significant challenges, particularly limited charge efficiency and cyclability, which arise from electrode degradation during operation. This degradation is primarily driven by corrosion and sulfation caused by water loss, ultimately compromising LAB’s performance, especially in heavy-duty applications. Recent studies have shown that incorporating carbon materials into both the positive and negative active masses can significantly enhance LAB's performance, especially in terms of capacity, cyclability and durability. In this regard, during the PhD which was carried out in collaboration with FIAMM Energy Technology spa, a multinational company active in the production and distribution of batteries for starting motor vehicles and for industrial use, a series of commercial carbon-based materials was carefully selected and screened for their physicochemical properties, including surface area, porosity, degree of graphitization, conductivity, and wettability. The most promising candidates were incorporated at various loadings in the positive active masses to create enhanced positive plates from scratch. Additionally, the inclusion of metal oxides, such as silica, has been found to improve battery lifespan by increasing the surface area and mechanical strength of the NAM. In this context, the combined effects of carbon and metal oxides on charge efficiency and cyclability, as well as water consumption of LABs, were explored throughout the PhD. Carbon compounds modified with metal oxides—specifically SiO2 and CeO2—were produced using a hard-template synthesis at varying precursor loadings. A variety of physicochemical analyses were conducted on them, including elemental analysis, N2 physisorption, Raman spectroscopy, XRD, SEM, EDX, and TEM, to assess the chemical composition, structure, and morphology of the synthesized compounds. Enhanced negative plates were also produced from scratch using these synthesized materials. To evaluate the electrical, electrochemical, and chemical properties of the novel electrodes, both positive and negative, 2V test cells were developed in both AGM and flooded configurations and assembled. Both standard and homemade procedures were employed to assess the impact of various compounds—both commercial and homemade—on the formation process, active material utilization, cyclability, and water consumption. Notably, a real-time monitoring protocol was developed for evaluating water loss, which combined electrochemical polarization with gas analysis. This procedure was designed for use in both AGM configuration (in accumulation mode) and flooded configuration (in flux mode) to examine how additives affect water consumption and related phenomena, including the OER, HER, corrosion, and recombination. The effect of incorporating carbonaceous materials on water consumption, as well as on the charge/discharge performance of lab-scale batteries, was compared with both commercial and homemade reference electrodes. Furthermore, tear-down analyses—including XRD, Raman spectroscopy, SEM, cross-sectional SEM, EDX and Hg-porosimetry—were performed on various positive and negative plates at different stages of the batteries’ lifespan, particularly following the curing process, after formation, and after electrical testing. These analyses aimed to investigate how different additives influenced the compositional, structural, and morphological properties of the specimens.