An in-depth study of heteroatom boosted anode for potassium-ion batteries

Metal sulfide materials have been investigated extensively as anodes for alkali metal ion batteries. In this work, the N-doped graphene/bismuth sulfide (NGBS) composites are prepared for potassium-ion batteries (PIBs) anode and deliver an excellent electrochemical performance in K-ion storage. The N-doped graphene armor can accommodate the large volume variation and the weak electrical conductivity of the bismuth sulfide electrode, but also provides more active sites for K-ion storage which obviously enhances the specific capacity. Moreover, the active sites of the graphene play a crucial role in restricting the "shuttle effect" of polysulfide by forming C-S bonds reversibly during electrochemical redox process and achieve the stable electrochemical cycles as a hybrid anode for PIBs. The K-ion insertion/deinsertion and the reversible C-S bonds formation of the NGBS electrode during the electrochemical cyclic process are revealed by the in-situ X-ray diffraction, in-situ Raman spectroscopy, cyclic voltammetry and X-ray photoelectron spectroscopy in detailed.