Sandwich-like MoS2@SnO2@C with High Capacity and Stability for Sodium/Potassium Ion Batteries

Sandwich-like MoS 2 @SnO 2 @C nanosheets are prepared by facile hydrothermal reactions. SnO 2 nanosheets can attach to exfoliated MoS 2 nanosheets to prevent restacking of adjacent MoS 2 nanosheets, and carbon transformed from polyvinylpyrrolidone is coated on MoS 2 @SnO 2 , forming a sandwich structure to maintain cycling stability. As an anode for sodium-ion batteries, the electrode greatly deliverers a high initial discharge specific capacity of 530 mA h g −1 and maintains at 396 mA h g −1 after 150 cycles at 0.1 A g −1 . Even at a large current density of 1 A g −1 , it can hold 230 mA h g −1 after 450 cycles. Besides, as an anode for K + storage, the electrode also shows a discharge capacity of 312 mA h g −1 after 25 cycles at 0.05 A g −1 . This work may provide a new strategy to prepare other composites which can be applied to new kind of rechargeable batteries.