Rationally constructing metallic Sn-ZnO heterostructure via in-situ Mn doping for high-rate Na-ion batteries

Developing a heterostructure for alloying-based anode for sodium-ion batteries (SIBs) is an efficient solution to accommodate volume change upon sodiation/desodiation and boost sodium storage since it combines the merits of each component. Herein, we report a metallic and microphone-like Sn-Zn_0.9Mn_0.1O heterostructure via an in-situ Mn doping strategy. Based on theoretical calculations and experimental results, the introduction of Mn into ZnO (a small amount of Mn also diffuses into the Sn lattice) can not only enhance intrinsic electronic conductivity but also reduce the Na⁺ diffusion barrier inside the Sn phase. When evaluated as anode for SIBs, the obtained heterostructures show a high reversible capacity of 395.1 mAh/g at 0.1 A/g, rate capability of 332 mAh/g at 5 A/g, and capacity retention of almost 100 % after 850 cycles at 5 A/g, indicating its great potential for high-power application of SIBs.