Pseudocapacitive boosts nanoparticles composed of sea urchin structure Bi2S3-xSex@rGO with high rate and capacity for sodium ion battery anode

The abundant reserve and low cost of sodium over lithium has prompted an enormous development for sodium-ion batteries(SIBs). SIBs are expected to replace lithium ion batteries in the future and be widely applied. Reliable anodes are one of the key issues in the commercial application of SIBs. Herein, an elaborate sea urchin-shaped Se-doped Bi2S3 (Bi2S3-xSex@rGO) electrode is designed by hydrothermal method for SIBs. The Bi2S3-xSex@rGO electrode exhibits an excellent rate capability (694 mAh g −1 at 2 A g−1)and high reversible capacity (701 mAh g −1 after 100 cycles at 0.1 A g −1), which are superior to those of most Bi2S3 for SIBs anode reported previously. Pseudocapacitive contribution is demonstrated as the main reason of prominent electrochemical performance of the Bi2S3-xSex@rGO electrode. The sea urchin-like structure is composed of bismuth sulfide nanoparticles, which promotes the pseudocapacitance behavior of the electrode. The pseudocapacitance promoted by rapid transport of sodium ions could extend to more advanced SIBs anodes.