Unravelling the structure-stability interplay of O3-type layered sodium cathode materials via precision spacing engineering

The O3-type layered oxide represents a highly promising candidate for sodium-ion batteries (SIBs). However, the intrinsic stability law of these cathodes remains elusive due to the complex phase transition mechanism and migration of transition metal (TM) ions. Here, we underscore how the ratio between the spacings of alkali metal layer and TM layer (R = dO-Na-O/dO-TM-O) plays a critical role in determining the structural stability and the corresponding electrochemical performance. We design a peculiar family of NaxMn0.4Ni0.3Fe0.15Li0.1Ti0.05O2 (0.55 ≤ x ≤ 1) composition that is thermodynamically stable as an O3-type structure even when R is as high as 1.969, far exceeding 1.62 that normal O3-type structures…

• NS
  Natural Science Foundation of Guangdong Province

  Award: No. 2023A1515140126