Recently, a unique class of heterostructures known as honeycomb layered oxides has gained attention as highenergy-density electrodes and electrolyte materials for their rich crystal chemistry that provides high cationic conduction and high voltages using Na and K ions . The general formula of this series of materials is A 2 M 2 DO 6 , A 3 M 2 DO 6 or A 4 M DO 6 , where M can be divalent or trivalent transition metal atoms such as Cr, Mn, Fe, Co, Ni, Cu, or some combination thereof; D rep- * kartik.sau@gmail.com resents pentavalent or hexavalent metal atoms such as Sb, Te, or Bi; and A can be alkali metal atoms such as Li, Na, or K . The structure in general consists of an array of parallel transition metal slabs with a distinct honeycomb arrangement of multiple M atoms surrounding D atoms in a layered framework of interposed A alkali atoms. Specifically, the tellurates in honeycomb layered oxides have been reported to produce the highest voltages (over 4V) to date . Thus, a thorough study on the cationic diffusion mechanism in honeycomb layered oxides based on tellurate (Na 2 LiFeTeO 6 ) presents an ideal platform for maximizing the cationic conduction.