Today, I gave a Monday Seminar at the Structural Chemistry Program, Uppsala University, discussing proton activities in aqueous batteries. A specific definition of proton activity refers to the effective proton concentration in an electrolyte, accounting for deviations from ideal behavior, while a more general definition deals with the interactions between protons and their surrounding environments, e.g., other water molecules, electrode materials, and interphases.

It is also worth mentioning that in connection with activity, excess Gibbs free energy, defined as the difference between the actual Gibbs free energy of the solution and that of an ideal solution with the same composition at the same temperature and pressure, measures the deviation of a real solution from an ideal solution. Both concepts are important in understanding the behavior of solutions in thermodynamics.

In today’s seminar, I elaborated on chemical signatures of proton activities by means of operando characterization techniques. I am now writing a manuscript on this topic, in collaboration with other colleagues. Stay tuned!