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One of the key challenges of sodium ion batteries is to develop sustainable, low-cost and high capacity cathodes, and this is the reason that layered sodium manganese oxides have attracted so much attention. However, the undesired phase transitions and poor electrolyte-electrode interfacial stability facilitate their capacity decay and limit their practical applications. Herein, we design a novel Al2O3@Na0.67Zn0.1Mn0.9O2 electrode to mitigate these problems, by taking the advantages of both structural stabilization and surface passivation via Zn2+ substitution and Al2O3 atomic layered deposition (ALD) coating, respectively. Long-range and local structural analyses during charging/discharging processes indicate that P2–P2’ phase transformation can be suppressed by substituting proper amount of Mn3+ Jahn-Teller centers with Zn2+, whereas excessive Zn2+ leads to P2-OP4 structure transition at low sodium contents and facilitates the electrode degradations. Furthermore, the homogeneous and robust cathode electrolyte interphase (CEI) layers formed on the Al2O3-coated electrodes effectively hinder the organic electrolytes from further decomposition. Therefore, our synergetic strategy of Zn2+ substitution and ALD surface engineering remarkably boosts the cycling performance of P2–Na0.67MnO2 and provides some new insights into the designing of highly stable cathode electrodes for sustainable sodium ion batteries.

The P2-type Na0.66Ni0.33Mn0.67O2 electrode is one of the most promising layered cathodes, which exhibits high average potential of 3.5 V versus Na+/Na. When working at the high voltage range beyond...

The key to breaking through the capacity limitation imposed by intercalation chemistry lies in the ability to harness more active sites that can reversibly accommodate more ions (e.g., Li

The capacity of the layered oxide cathode in a sodium ion battery can be increased by harnessing anionic redox. However, the extra capacity induced by anionic redox comes at the expense of reversibility due to the irreversible oxidation and subsequent loss of oxygen. Here, we report a universal strategy of improving the reversibility of oxygen redox in sodium layered oxides by regulating the superstructural motifs. The intrinsic chemical properties of superstructural motifs can be directionally altered by modulating the interionic interactions, and the rational integration of selected superstructural motifs can result in advanced materials with target performance. As a demonstration, a novel cathode comprising both Mg@Mn6 and Li@Mn6 superstructural motifs is designed and synthesized with inherently inhibited oxygen loss and significantly improved cyclic reversibility. Detailed characterizations on the atomic-level structure and chemistry of materials revealed that the pinning effect of the Mg@Mn6 superstructural motif is critical to maintain a stable layered structure. The findings from this work open up new routes for the design and development of next-generation high energy cathodes with target performance.