Effect of pore structure on the adsorption performance of magnesium oxide for thermal cells

The powders with different pore structures were obtained by adjusting the ratio of ammonia to magnesium salt. The morphology and pore structure of the powders were analyzed by XRD, SEM, TEM, FT-IR and N2 adsorption-desorption methods to investigate the effect of pore structure on the electrolyte leakage rate and hot cell performance.

The results showed that: the ratio of precipitant can significantly change the pore structure, when n(NH3-H2O):n(Mg2+)=1.5:1, a large number of mesopores were formed, the specific pore volume increased to 0.179 cm3/g, the specific surface area reached 30.91 m2/g, and the leakage rate was only 6 mg/cm2 in the electrolyte binder plate with 35% MgO content (mass fraction).The suitable pore size for adsorption of Li Cl -KCl eutectic salt of magnesium oxide pore size should be in the range of 2~200 nm. The high leakage rate of electrolyte leads to short average operating time of hot cell, and the small pore size of magnesium oxide will increase the average activation time of hot cell.