Taking all the results together, most side reactions for the studied cell with NaMNO as cathode active material are caused by oxidation reactions above 3.8 V. This includes the evolution of gases seen at lower potentials after cycle one in the cells cycled to 4.25 V which proves that the reactants causing the gases evolution at low potentials around 3.3 V are mainly due to side products formed at higher potentials in the previous cycles.