Metal Substitution versus Oxygen-Storage Modifier to Regulate the Oxygen Redox Reactions in Sodium-Deficient Three-Layered Oxides

Sodium-deficient nickel-manganese oxides with three-layered stacking exhibit the unique property of dual nickel-oxygen redox activity, which allows them to achieve enormous specific capacity. The challenge is how stabilize oxygen activity during cycling. This study demonstrates that P3-Na2/3Ni1/2Mn1/2O2 both Na+ and Li+ intercalation can be regulated by design oxide architecture includes target metal substituents (such as Mg2+ Ti4+) storage modifiers CeO2). Although substitution for nickel Ti4+ amplifies intensifies interaction NaPF6- LiPF6-based electrolytes, influence mainly suppress deposition electrolyte decomposed products MnF2). CeO2-modifier has a much stronger effect on than substituents; thus, highest capacity attained. In addition, tunes electrode–electrode eliminating MnF2. As result, Mg-substituted modified CeO2 displays high capacity, excellent cycling stability exceptional rate capability when used cathode in Na-ion cell, while Li-ion best performance achieved Ti-substituted CeO2.