He suggested that during discharge, lead sulfate (PbSO₄) forms on both the positive and negative plates of the battery. This theory explained the decrease in the battery's voltage during discharge and the need for charging to reverse the process.
However, it's important to note that while the double sulfate theory is a useful simplification, it doesn't fully account for all the complex electrochemical reactions occurring within the battery. Modern understanding of the lead-acid battery is more nuanced and involves other factors like hydrogen evolution and lead oxide formation.
