Engineering heterogeneous SnO2/SnS2 quantum dots anchored on graphene oxide as anode materials for high-performance lithium-ion batteries

Tin dioxide (SnO 2 )-based materials with renowned conversion-alloying hybrid mechanism represent great potential as anodes for next-generation lithium-ion batteries (LIBs). Nevertheless, their commercial applications are still plagued by fast capacity decay and insufficient rate capability originated from sluggish reaction kinetics and irreversible conversion reaction. Herein, heterogeneous SnO 2 /SnS 2 quantum dots are carefully constructed on graphene oxide (SnO 2 /SnS 2 QDs@GO) via one-step hydrothermal synthesis leveraging well-matched bandgaps of SnO 2 and SnS 2 , in which GO not only provides enough negative charges to restrict the nucleation of QDs, but also is employed as robust conductive network to reinforce the structural stability of the electrode. Experimental and first-principles calculation results confirm that the constructed heterointerface promotes electronic conductivity and accelerates interfacial charge transfer kinetics while simultaneously lowering Li 2 O decomposition energy barrier to realize high reaction reversibility, ultimately favoring excellent rate capability and cyclability. Moreover, the built-in electric field induced by SnO 2 /SnS 2 heterojunction greatly boosts electronic/ionic transport kinetics. Endowed with the elaborate structure combining intrinsic and extrinsic advantages, the cell assembled with SnO 2 /SnS 2 QDs@GO electrode presents high reversible capacity of 1216.9 mAh g −1 after 100 cycles at 0.1 A g −1 and desirable long-cycle stability over 1500 cycles at 5.0 A g −1 . Therefore, this work may provide new insights into engineering semiconductor-based heterojunction anode for advanced LIBs.