Constructing SnO2/SnSe2 heterostructures anchored on reduced graphene oxide for advanced Lithium-ion batteries.

Tin-based compounds have an ultrahigh theoretical capacity and low oxidation-reduction potential, making them as a very important type of anode matrix for lithium-ion batteries (LIBs). Nevertheless, the enormous volume dilatation causes structural collapse, limiting its cyclic stability. Herein, a nanoscale SnO2/SnSe2@rGO has been designed, in which the interface of SnO2/SnSe2 heterostructure generates a built-in electric field, improving charge transfer efficiency. And rGO, as a 3D interconnection network coating SnO2/SnSe2 nanoparticles, improves conductivity and serves as a buffer medium for volume expansion. DFT calculations confirm that the formation of built-in electric field enhances the adsorption energy of Li+ and reduces the migration energy barrier. As expected, the initial capacity of the SnO2/SnSe2@rGO electrode can reach 1405.9 mAh g-1 at 2.0 A g-1. The reversible capacity is 1459.1 mAh g-1 at 0.1 A g-1 after 50 cycles, with 78.1 % capacity retention. Finally, a SnO2/SnSe2@rGO//LiFePO4 (LFP) full battery was assembled, which exhibits a high capacity of 213.1 mAh g-1 at 0.1 A g-1 and energy density of 492.8 Wh kg-1 at 270 W kg-1. The design of this nanoscale heterostructure provides a feasible strategy for developing LIBs anodes with enhanced capacity and extended lifespan.