Realizing discrepant oxygen-redox chemistry in honeycomb superlattice cathode via manipulating oxygen-stacking sequences

[Display omitted] •Manipulating oxygen stacking facilitates discrepant oxygen redox chemistry.•Strong oxygen redox behavior occurs in P3 stacking structure than P2 mode.•Oxygen layer sliding is severe for P3 to O3 stacking compared to P2-O2 couple. Anion redox chemistry in honeycomb-superlattice transition metal layer oxides plays a profound role on improving energy density in Na-defect P-type layer structure with pure cationic redox for sodium-ion batteries (SIBs). The correlation regarding variant oxygen-stacking sequences, discrepant oxygen-redox chemistry and electrochemical oxygen-layer sliding is vital, but is not established. Driving from controlling oxygen stacking sequences, the discrepant anionic redox chemistry is realized within Mg-Mn honeycomb-superlattice layer structure. Specifically, the P3-ABBCCA structure exhibits lower oxygen-redox trigger potential and higher oxygen-redox activity, resulting in a higher initial discharge capacity 202.0 mAh g−1 than 152.9 mAh g−1 of P2-ABBA structure. However, P3-ABBCCA stacking structure easily suffers grievous oxygen-sliding coupled with continuous oxygen activation at high cutting-off operation voltage 4.5 V, and finally transforms into O3-ABCABC structure. Compared with oxygen-stacking configuration of P2-ABBA structure, the oxygen-sliding of P3-ABBCCA structure is more irreversible, resulting in sluggish kinetics, rapid capacity degradation and discharge voltage fade during cycling. This study provides a new perspective and guidance on facilitating oxygen-redox chemistry reform in superlattice Na-defective layer cathode of SIBs.