More significant than the reduction in total gas evolution is the reduction in cycle dependent gas evolution. For the 2G containing cell, the H2 evolution shows only a small cycle dependent increase above the expected baseline. For the PC containing cell, the overall H2 evolution is about twice as high as for the Na|Na symmetric cell, but there is no consistent cycling dependent evolution. It can be also seen that reducing the cut-off potential to 3.8 V prevents the formation of CH4, dimethyl ether and propene, respectively. In the 2G containing cell, a small and decaying CO2 evolution is found. This might originate from a chemical reaction with the sodium metal or the slow decomposition of the carbonate impurities of the cathode that, due to the lower cut-off potential, occurs now over several cycles. In the PCcontaining cell, the CO2 evolution is a little higher compared to the Na|Na symmetric cell, shows small peaks at potentials above 3.3 V and the signal slightly increases over cycling.