  What is the maximum voltage of a cell with a given electrochemical reaction?
The answer to this question has been given more than a century ago by Walther
Nernst and bears his name. Unfortunately, the assumptions behind the answer
have been forgotten by many authors, which leads to wrong forms of the Nernst
relation. Such mistakes can be overcome by applying a correct thermodynamic
derivation independently of the form in which the reaction is written. The
correct form of Nernst relation is important for instance in modelling of
vanadium redox flow batteries or zinc-air batteries. In particular, the
presence of corrosion can impact the OCV in the case of zinc-air batteries.
