Sn is considered to be one of the most promising SIBs anode materials due to its high theoretical capacity，lower potential，environmental-friendly and non-toxic． But in the process of sodiation/desodiation， volume expansion will occur，resulting in the battery capacity and cycle stability and other electrochemical performance degradation． Sn/SnO x /C nanocomposites were prepared by a simple one-step hydrothermal

synthesis method． The nanostructure is composed of nanospheres encapsulated in a continuous carbon thin layer．The nanostructure can shorten the transmission distance of Na + ，and the carbon network can effectively improve the electrical conductivity of the material，at the same time，it can slow down the volume expansion of the material in the process of sodiation/desodiation．The electrode retains a discharge capacity of 372 mAhg－1and maintains 344 mAhg－1 after 50 cycles at a 0．15 C rate．The capacity retention rate was about 92．2%．These results show good cycle stability and electrochemical stability．