Promoting K ion storage property of SnS2 anode by structure engineering

Abstract

As indispensable components of potassium ion batteries (KIBs), anode materials are on the focus and their developments are important for boosting the application of KIBs. Tin sulfide (SnS2) is considered as an ideal KIBs anode material owing to its high theoretical capacity (733 mAh g−1) and the unique layered structure. However, the huge volume deformation and potassium polysulfide intermediates dissolution hinder the enhancement of the electrochemical performance of SnS2 anode. Herein, SnS2 nanosheets supported by N, S-doped carbon (N, S-C/SnS2 nanosheets) were synthesized by an in-situ carbonization and sulfuration method with one step. In the formed architecture, the N, S-doped carbon not only works as matrix to stabilize the microstructure of the hybrid material, but also serves as the reservoir to trap polysulfides for alleviating the loss of sulfur element in SnS2. Thanks to these merits, a high reversible capacity (614.8 mAh g−1 at 0.1 A g−1), as well as good rate capability (104.5 mAh g−1 at 2.0 A g−1) are achieved by the N, S-C/SnS2 nanosheets electrode. This work offers a concise method to construct SnS2 hybrid material, and demonstrates that K+ ion storage property of conversion-alloy reaction mechanism sulfide anodes can be remarkably enhanced by elegant structure design.