Sn-C bonding riveted SnSe nanoplates vertically grown on nitrogen-doped carbon nanobelts for high-performance sodium-ion battery anodes

SnSe is a promising anode material in sodium-ion batteries (SIBs) due to its high theoretical capacity (780 mA h g−1) and natural abundance. Herein, we report SnSe nanoplates vertically grown on nitrogen-doped carbon (SnSe/NC) with strong Sn-C bonding for high-performance anode in SIBs, which are synthesized by a facial cation-exchange strategy. The vertically grown SnSe nanoplates with large interplanar spacing (0.58 nm), strong electronic coupling of Sn-C bonding between SnSe and NC facilitate the fast electron/ion transfer, enabling high pseudocapacitive Na-ion storage and enhanced power capability. Density functional theory calculations demonstrate that the presence of N heteroatoms in NC matrix has a pivotal influence on the formation of Sn-C bonding to stabilize the SnSe/NC structure. Moreover, the SnSe nanoplates of SnSe/NC exhibits low interlayer Na+diffusion barrier (0.1 eV) and low energy barrier (0.14 eV/uc) from discharged product to pristine SnSe/NC, implying the fast Na+diffusion capability and good reversibility. Consequently, the SnSe/NC exhibits large capacities of 723 and 88 mA h g−1at 0.025 and 20 A g−1, respectively, and 82% capacity retention for over 200 cycles at 2 A g−1, boosting promising applications in high-performance SIBs.