Microkinetics of the reactionNO3-⇌NO2-+0.5 O2i

A high-rate and high-efficiency molten-salt sodium–oxygen battery

“…By fitting the O 2 consumption curve over the first 3 min we determined a rate of ∼0.18 mmol h −1 , corresponding to a current density of 25 mA cm −2 geo and indicating that the reactions of Na 2 O and/or NaNO 2 with O 2 can be very fast. This finding is in agreement with previous work 55 that indicates that NO 2 − can be oxidized by O 2 to form NO 3 − in bulk NaNO 3 /KNO 3 molten salt at temperatures over 573 K.…”

Demonstration of the stabilization of solar salt at 620 C with a semi-closed configuration in a 100 kg-scale

“…In the following, two experiments (V1 and V2) are shown and discussed. The results of both experiments are compared to published lab-scale experiments from Sötz et al performed in a purged system in a mg- and g-scale with respect to the chemical equilibrium and with experiments in a small 1.5 g scale for comparison of the kinetic behavior to identify similarities and up-scaling effects [ [20] , [21] , [22] ]. Additionally, a short study (V3) on the regeneration of the degenerated and decomposed Solar Salt remaining after both experiments was performed and discussed in the chapter Regeneration.…”

“…(mg- and 100 g-scale) but are shifted to higher ln K at 560 °C ( Fig. 5 ) [ 20 , 21 ]. Those shifts can be ascribed to different reasons.…”

Solar Salt – Pushing an old material for energy storage to a new limit

“…The values at both 500 and 560 °C are in agreement with previously published thermodynamic data. [5,14,28] Therefore, it is reasonable to interpret the salt composition towards the end of the experiments as equilibrium composition with regard to the nitrate and nitrite content. Also, it becomes obvious that the applied experimental method is suitable for comparisons with other equilibrium studies.…”

“…[7] Experimental methods to determine a nitrate salts thermal stability limit and authors of this work and a thorough review will therefore not be provided here. [14] As a summary, there is consensus that a defined nitrate-nitrite equilibrium is established at 560 °C in air with around 95 mol% 𝑁𝑂 3 − and 5 mol% 𝑁𝑂 2 − . Nissen and Meeker [5] demonstrated, that by increasing the 𝑃 𝑂 2 the equilibrium of reaction 1 can be shifted to the nitrate side substantially, resulting in significantly lower nitrite concentrations at the same temperature.…”