Interlayer Expanded SnS2 Anchored on Nitrogen-Doped Graphene Nanosheets with Enhanced Potassium Storage

Potassium-ion batteries (PIBs) are promising candidates to substitute lithium-ion batteries (LIBs) as large-scale energy storage devices. However, developing suitable anode materials is still a great challenge that has limited the anticipated application of PIBs. Herein, the interlayer expanded SnS 2 nanocrystals anchored on nitrogen-doped graphene nanosheets (SnS 2 @NC) are synthesized following a facile one-step hydrothermal strategy. Relying on the exquisite nanostructure with larger interlayer spacing, the K + ions diffusion and charge transfer will be accelerated. In addition, the intense coupling interaction between nitrogen-doped graphene nanosheets and SnS 2 can endow a sturdy nanostructure, avoiding the collapse and aggregation of SnS 2 nanocrystals upon cycling. Based on the above merits, the as-prepared SnS 2 @NC anode exhibits improved electrochemical performanc (desirable rate capability of 206.7 mAh g −1 at 1000 mA g −1 and advanced cyclic property of 262.5 mAh g −1 , while after 100 cycles at 500 mA g −1 ). More importantly, multistep reactions of K + storage mechanism combining with intercalation, conversion and alloying reactions are clearly illustrated by combined in-situ XRD measurement and ex-situ TEM detection. This strategy of enhancing K + storage performances has a great potential for other electrode materials. Graphical Superlative : The unique interlayer expanded SnS 2 nanocrystals anchored on nitrogen-doped graphene nanosheets are exquisitely constructed and used as potassium-ion battery anode with enhanced specific capacity and long cyclic stability. This rationally strategy may provide further applicability in other energy storage systems.