Facile construction of CoSn/Co₃Sn₂@C nanocages as anode for superior lithium‐/sodium‐ion storage

CoSn/Co 3 Sn 2 @C with nanocages structure is obtained via a facile coprecipitation method with polydopamine coating followed by an annealing procedure. Due to the uniform nanocages structure, CoSn/Co 3 Sn 2 @C moderates the volume fluctuation, ensures good infiltration with electrolyte, and provides more pathways for ions/electrons transport. Moreover, the introduction of carbon inhibits the agglomeration of Sn 0 nanoparticles, improves electronic conductivity, and offers a buffer matrix to protect the nanocage structure from destructing. As lithium‐ion batteries (LIBs) anode, this CoSn/Co 3 Sn 2 @C anode possesses 622.3 mAh g −1 after 300 cycles at 200 mA g −1 and 571.2 mAh g −1 for another 1600 cycles at 1000 mA g −1 . CoSn/Co 3 Sn 2 @C can maintain a capacity of 791.1, 748.3, 678.4, 569.8, 461.0, and 367.0 mAh g −1 at 65, 130, 0260, 650, 1300, and 2600 mA g −1 , respectively. For sodium‐ion batteries (SIBs), the CoSn/Co 3 Sn 2 @C can attain a specific capacity of 290.2, 246.6, 205.1, 166.0, 142.3, and 124.1 mAh g −1 at 80, 160, 320, 800, 1600, and 3200 mA g −1 , respectively. CoSn/Co 3 Sn 2 @C anode earns 171.9 mAh g −1 after 150 cycles at 1000 mA g −1 . This design of strategy provides ideas for the fabrication of porous anode materials and will promote the development of LIBs and SIBs.