Effect of of on Na plus extraction

This study investigated the effect of intergranular connectivity when Na+ was extracted from polycrystalline NaAlB14 to the Y-type zeolite via anisotropic ion diffusion control (ADC) and high-pressure diffusion control (HPDC) methods. Despite the low chemical intergranular connectivity in NaAlB14 without pre-annealing, Na+ was homogeneously extracted via HPDC process. Although the HPDC can form a strong physical compression between particles, the intergranular domain of the sample was oxidized by the backflow of oxide ions from the zeolite. Such oxidization can be solved by pre-annealing for chemical intergranular connectivity. In the case of Na+ extraction via ADC process, Na+ remained at the cathode side even after the treatment for 230 h. From the comparison between ADC and HPDC processes, a strong physical compression between particles by applying pressure can promote the diffusion of Na+. Therefore, pre-annealing and high-pressure applications are essential for ion diffusion control techniques.