SnSe/r-GO Composite with Enhanced Pseudocapacitance as a High-Performance Anode for Li-Ion Batteries

Ultrafine SnSe nanocrystals uniformly dispersed on the reduced graphene oxide (r-GO) surface were synthesized by a facile one-step solvothermal technique. The as formed SnSe with size less than 5 nm connect with r-GO by Sn-C and Sn-O-C bonds. This chemically bonded SnSe/r-GO composite exhibits enhanced electrochemical properties with which the reversible capacity can be maintained around 1046 mAh g(-1) at 200 mA g(-1) and similar to 514 mAh g(-1) at 2000 mA g(-1). Further analysis finds that the superior Li-ion storage performance of the SnSe/r-GO electrode is dominated by a surface-controlled pseudocapacitive behavior, which contributes 88.7% of the total capacity at 0.5 mV s(-1). Such a high ratio of pseudocapacitive storage in the SnSe/r-GO electrode could be ascribed to the synergistic effect of chemically bonded ultrafine SnSe nanocrystals with conductive r-GO networks.