The fabrication of hierarchical porous nano-SnO2@carbon@humic acid ternary composite for enhanced capacity and stability as anode material for lithium ion battery

High performance of SnO2 @C@HA ternary anode material was fabricated by microwave-assisted hydrothermal and subsequent calcination process in the presence of humic acid (HA) and super P. In the calcination process, tin hydroxide is converted to tin oxide and then be crystallized. For comparison purpose, two other composites including SnO2 @C and SnO2 @HA are also prepared, and the structures, morphology and electrochemical performances of these composites are investigated in detail. The results showed that the addition of HA improved the dispersibility of the SnO2 nanoparticles and the specific surface area of the composite. Electrochemical measurement showed that the SnO2 @C@HA anode exhibited high retention capacity during charge-discharge cycling as compared to that of the binary systems, which was attributed to the porous hierarchical structure and high conductivity of SnO2 @C@HA. The reversible specific capacity of SnO2 @C@HA anode can be maintained at 612.0 mA h g−1 after 500 cycles at a current density of 500 mA g−1.