Ultrafine SnSSe/multilayer graphene nanosheet nanocomposite as a high-performance anode material for potassium-ion half/full batteries

Layer-structured SnSSe attracts much attention as an anode material for potassium storage due to its large theoretical capacity. Unfortunately, their practical application is severely restrained by the dramatic volumetric variation of SnSSe. Herein, we synthesize ultrafine SnSSe/multilayer graphene nanosheet (SnSSe/MGS) by a vacuum solid-phase reaction and subsequent ball milling. Owing to the strong synergistic effect between the two components, the obtained SnSSe/MGS nanocomposite exhibits a high reversible capacity (423 mAh g−1 at 100 mA g−1), excellent rate property (218 mAh g−1 at 5 A g−1), and stable cycling performance (271 mAh g−1 after 500 cycles at 100 mA g−1) in potassium-ion half batteries. Moreover, the full cell assembled by the SnSSe/MGS anode and the potassiated 3,4,9,10-perylene-tetracarboxylic aciddianhydride cathode shows excellent electrochemical performance between 0.2 and 3.3 V (209 mAh g−1 at 50 mA g−1 after 100 cycles). The presented two-step synthesis strategy of SnSSe/MGS may also provide ideas to craft other alloy-type anode materials.