SnO2 is a theoretically excellent transformed anode material with high theoretical capacity for SIBs. However, SnO2 faces serious volume effect and high resistance, which greatly damages its electrochemical performance. Given that, the SnS-SnO2 heterostructures is constructed with special internal electric field, which is beneficial to promote the transfer ability of sodium ions. Besides, the graphene oxide (GO) modification is carried out to isolate the intrinsic materials from direct contact with electrolyte, and alleviate volume expansion of the anode, ultimately promote the electrochemical performance. Furthermore, the structure and the conductivity characteristics of SnS, SnO2 , SnS-SnO2 and SnS-SnO2 @ GO are simulated respectively by first principles and are compared with the correspondence experiment results to verify the accuracy of established models. Owing to the special p-n junction in SnS-SnO2 @GO heterostructures, the resistance of SnS-SnO2 @GO can be reduced to 36.23 Ω, much lower than that of SnO2 (Rct=341.9 Ω). Notably, the combination of GO has effectively alleviated the volume expansion of SnS-SnO2 @GO electrodes, and present excellent capacity higher than 384.7 mAh g-1 after 100 cycles. Thus, the efficient synthesis of SnS-SnO2 @GO heterostructure electrodes with excellent performance for sodium storage is expected to provide valuable direction for SIBs anode materials.
Keywords: Coulombic efficiency; SnS−SnO2; heterostructures; internal electric.
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