Study of the stability and adsorption of H2O on the surfaces (110) and (101) of b-PbO2
Lead acid batteries (LABs) are one of the main technological innovations in 20th-century energy storage. However, to this day, LABs dominate the global battery market due to their high efficiency, safety, recyclability, and low cost. Lead acid batteries have different disadvantages, such as corrosion in the current collector, sulphation in the electrodes, degradation of the active material, and water loss, the latter being one of the most important. The loss of water in LABs can be studied through the interaction of the active material and the H2O molecules. The active material is made up of a mixture of spongy Pb, a-PbO2, and b-PbO2 the latter being in a higher percentage. b-PbO2 has a tetragonal crystalline phase, with surfaces (110) and (101) being the most stable and reactive. In this work, density functional theory (DFT), implemented in Quantum Espresso software, is used to calculate the stability and reactivity of the (101) and (110) surfaces of b-PbO2, and b-PbO2-OX (with reticular oxygen). The adsorption energies of a H2O molecule on surfaces (101) and (110) were also studied. The results indicate high thermodynamic stability and reactivity of the (101) surface compared to the (110) surface. Molecular and dissociative adsorption modes are on the (101) and (110) surfaces, respectively, which are promoted by the strong influence of reticular oxygen (OX).