Facile synthesis of SnSe2 nanoparticles supported on graphite nanosheets for improved sodium storage and hydrogen evolution

Abstract SnSe 2 attract enormous attention in sodium-ion batteries since it has a high theoretical specific capacity of 756 mAh g −1 . However, the large volume expansion of SnSe 2 during Na + insertion/extraction processes seriously affects the cyclic stability of SnSe 2 -based electrodes. Herein, 5 nm SnSe 2 nanoparticles supported on the graphite nanosheets are synthesized by two-step high-energy ball milling to obtain SnSe 2 /graphite nanosheet nanocomposite. By virtue of the ultrafine SnSe 2 nanoparticles and the porous carbon skeleton constructed by highly conductive graphite nanosheets, the as-obtained SnSe 2 /graphite nanosheet nanocomposite presents a high specific capacity of 638.6 mAh g −1  at 200 mA g −1 , excellent rate capacity of 517.8 mAh g −1  at 5 A g −1 , and ultralong cyclic life (252.9 mAh g −1 after 4000 cycles at 2 A g −1 ), which are superior to the previously reported SnSe 2 -based composites. Ex-situ X-ray diffraction, Raman mapping, high-resolution transmission electron microscope, and X-ray photoelectron spectroscopy characterizations show that the crystal structure of SnSe 2 is reversible during sodium ions insertion/extraction processes and the distribution of SnSe 2 nanoparticles on graphite nanosheets remains uniform. Moreover, this nanocomposite can not only be used as a high-performance anode for sodium-ion full cells, but also as an improved electrocatalyst for hydrogen evolution reaction.