Lyotropic Liquid Crystalline Mesophase of Sulfuric Acid–Nonionic Surfactant Stabilizes Lead(II) Oxide in Sulfuric Acid Concentrations Relevant to Lead Acid Batteries

摘要

Concentrated sulfuric acid (SA) and nonionic surfactant (C_(12)H_(25)(OCH_(2)CH_(2))_(10)OH, C_(12)E_(10)) form lyotropic liquid crystalline (LLC) mesophases in a broad range of SA concentrations; the SA/C_(12)E_(10) mole ratio may vary from 2 to 11 in the LLC mesophases in the presence of a small amount of water. The mesophase is hexagonal at low SA concentration and cubic at higher concentrations. Three different compositions were prepared (one hexagonal and two cubic) with the SA/C_(12)E_(10) mole ratio of 2.5, 6, and 9, denoted as 2.5LC, 6LC, and 9LC, respectively. They all display electrochemical SA activity in Pt and Pb systems. Most interestingly, they show the electrochemical formation of stable PbO species in a deeply acidic medium as evidenced by the X-ray diffraction, cyclic voltammetry, and linear sweep voltammetry experiments. The preferable properties of PbO over PbSO_(4) for lead acid batteries (LABs) make it uniquely positioned as a superior gel electrolyte for the LABs that would mitigate sulfation.