Electrochemical Calorimetry of the Zinc and Bromine Electrodes in Zinc‐Bromine and Zinc‐Air Batteries

Abstract

Direct calorimetric measurements are reported on three half‐cell reactions of interest in zinc battery thermodynamics: the Zn/Zn2+ reaction in aqueous Br− solution; the reaction at Pt and the reaction in alkali. An experimental procedure is described for determining the single reaction heats, observable as TΔS quantities, in both directions of the above reactions, thus providing a method for eliminating, by difference, the Joule heating effects which are unavoidable in the course of measurements at finite currents. Corrections for entropies of transport are made and discussed. Under certain conditions, where Zn corrosion can occur with evolution of , the TΔS heat change for that process is also determinable. Some heat changes for overall cell reactions are also determined.